Magento – Re-Write Toolbar for grid on front side magento

I want to override the Product grid tool-bar for custom work in my module.I inlcude my filters in the filters array but the product grid is not executing my code when i select my filter like , i want to add best seller and most viewed filters to toolbar ,My config.xml code is :

<catalog>
             <rewrite>
               <product_list_toolbar>Mymodule_Block_Catalog_Product_List_Toolbar</product_list_toolbar>
            </rewrite>
         </catalog>.

I created a block class for that like :

<?php

class Mymoudle_Block_Catalog_Product_List_Toolbar extends Mage_Catalog_Block_Product_List_Toolbar
{


    public function getAvailableOrders()
    {
      $vari = Mage::helper('Mymoudle')->getMethods();

        return $vari;
    }
 public function getCurrentDirection()
    {
        $dir = parent::getCurrentDirection();
        $url = strtolower($this->getRequest()->getParam($this->getDirectionVarName()));   
        if (!$url){
            $dir = 'desc';
        }    
        return $dir;
    }  

    public function setCollection($collection)
    {
       parent::setCollection($collection);        


        $methods = $this->getMethods();
        if (isset($methods[$this->getCurrentOrder()])){
            $methods[$this->getCurrentOrder()]->apply($collection, $this->getCurrentDirection());
        }
        if($this->getCurrentOrder() == 'bestselling'){
        if(Mage::helper('Mymoudle')->getbestperiod() > 0){
            $limit = (int)$this->getLimit();
            $collection = Mage::helper('Mymoudle')->getBestsellingProducts($limit,$this->getCurrentDirection());
        }
    }
      if($this->getCurrentOrder() == 'most_viewed'){
        if(Mage::helper('Mymoudle')->getviewdtimeperiod() > 0){
            $limit = (int)$this->getLimit();
             $collection = Mage::helper('Mymoudle')->getMostViewedProducts($limit);
        }
        }



echo $collection->getSelect();

        return $collection;
    }
    public function getCollection()
    {
        return $this->_collection;
    }
}.

this is my Helper class :

<?php

class Mymodule_Helper_Data extends Mage_Core_Helper_Abstract
{
     const SORT_PRODUCTS_STATUS             = 'sortproducts/setting/settings';
     const SORT_PRODUCTS_POSITION_FILTER    = 'sortproducts/general/position_filter';
     const SORT_PRODUCTS_BEST_PERIOD        = 'sortproducts/general/best_period';
     const SORT_PRODUCTS_VIEWD_PERIOD       = 'sortproducts/general/viewed_period';
     const SORT_PRODUCTS_WHISLIST_PERIOD    = 'sortproducts/general/wishlist_period';

     public function getextEnable()
     {
            return Mage::getStoreConfig(self::SORT_PRODUCTS_STATUS);        
     }
    public function getpositionstatus()
    {
            return Mage::getStoreConfig(self::SORT_PRODUCTS_POSITION_FILTER);
    }
    public function getbestperiod()
    {
            return Mage::getStoreConfig(self::SORT_PRODUCTS_BEST_PERIOD);
    }
    public function getviewdtimeperiod()
    {
            return Mage::getStoreConfig(self::SORT_PRODUCTS_VIEWD_PERIOD);
    }
    public function getwishlistperiod()
    {
            return Mage::getStoreConfig(self::SORT_PRODUCTS_WHISLIST_PERIOD);
    }
    public function getMethods()
    {

         $attributes = Mage::getSingleton('eav/config')
        ->getEntityType(Mage_Catalog_Model_Product::ENTITY)->getAttributeCollection()->AddFieldToFilter('used_for_sort_by','1');

        foreach ($attributes as $attr) {

            $value = $attr->getAttributeCode();
            $label = $attr->getStoreLabel() ? $attr->getStoreLabel() : $attr->getFrontendLabel();
           $arr[$value]  = $label;
}

    if($this->getbestperiod() > 0)
     {
        $t = array('bestselling' => $this->__('Best Seller'));
     }
     if($this->getviewdtimeperiod() > 0)
     {
        $ts = array('most_viewed' => $this->__('Most Viewed'));
     }
     $arr = array_merge($arr,$ts);
     $scd = array_merge($arr, $t);
     if($this->getpositionstatus())
     {
        $scd = array_merge($scd,array('position' => $this->__('Position')));
     }

        asort($scd);       
        return $scd;

    }
  public function aasort (&$array, $key) {
            $sorter=array();
            $ret=array();
            reset($array);
            foreach ($array as $ii => $va) {
                $sorter[$ii]=$va[$key];
            }
            asort($sorter);
            foreach ($sorter as $ii => $va) {
                $ret[$ii]=$array[$ii];
            }
            $array=$ret;
    }

    public function getBestsellingProducts($pagecount,$orderby)
{   
    // number of products to display
    $productCount = $pagecount; 

    // store ID
    $storeId    = Mage::app()->getStore()->getId();

    // get today and last 30 days time
    $today = time();
    $last = $today - (60*60*24*$this->getbestperiod());

    $from = date("Y-m-d", $last);
    $to = date("Y-m-d", $today);
    if($orderby == 'asc')
    {
        $neworder = 'desc';
    }elseif($orderby == 'desc')
    {
        $neworder = 'asc';
    }
    // get most viewed products for current category
    $products = Mage::getResourceModel('reports/product_collection')
                    ->addAttributeToSelect('*')     
                    ->addOrderedQty($from, $to)
                    ->setStoreId($storeId)
                    ->addStoreFilter($storeId)                  
                    ->setOrder('ordered_qty', $neworder)
                    ->setPageSize($productCount); 

    Mage::getSingleton('catalog/product_status')
            ->addVisibleFilterToCollection($products);
    Mage::getSingleton('catalog/product_visibility')
            ->addVisibleInCatalogFilterToCollection($products);

    return $products; 
    }
     public function getMostViewedProducts($pagecount)
{   
    // number of products to display
    $productCount = $pagecount; 

    // store ID
    $storeId    = Mage::app()->getStore()->getId();

    // get today and last 30 days time
    $today = time();
    $last = $today - (60*60*24*$this->getviewdtimeperiod());

    $from = date("Y-m-d", $last);
    $to = date("Y-m-d", $today);

    // get most viewed products for current category
    $products = Mage::getResourceModel('reports/product_collection')
                    ->addAttributeToSelect('*')     
                    ->addOrderedQty($from, $to)
                    ->setStoreId($storeId)
                    ->addStoreFilter($storeId)                  
                    ->addViewsCount()
                    ->setPageSize($productCount); 

    Mage::getSingleton('catalog/product_status')
            ->addVisibleFilterToCollection($products);
    Mage::getSingleton('catalog/product_visibility')
            ->addVisibleInCatalogFilterToCollection($products);

    return $products; 
    }
}.

When i select my custom filter the getselect() code shows that my code runs but nothing happend to grid.The problem is grid not showing my cusotm filter results.
thanks in advance