Magento Newsletter Subscriber – Adding Extra Fields Not Working

I try to add a type(extra field) to newsletter_subscriber table.

Following is my approach to add the field.

1.Add new column to newsletter_subscriber table(types)

2.Add types check box to subscribe.phtml file

3.Create an observer for newsletter_subscriber_save_before event

My Config.xml file is

<?xml version="1.0"?>
<config>
<modules>
    <Wired_Newsletters>
        <version>0.1.0</version>
    </Wired_Newsletters>
</modules>
<global>
    <models>
        <newsletters>
            <class>Wired_Newsletters_Model</class>
        </newsletter>
    </models>
    <events>
        <newsletter_subscriber_save_before>
            <observers>
                <newsletters_add_types>
                    <class>newsletters/observer</class>
                    <method>newsletterSubscriberSave</method>
                </newsletters_add_types>
            </observers>
        </newsletter_subscriber_save_before>
    </events>
 </global>   

My observer.php file(\app\code\local\Wired\Newsletters\Model)

<?php
class Wired_Newsletters_Model_Observer extends Varien_Event_Observer
{
public function newsletterSubscriberSave($observer){
    $subscriber = $observer->getEvent()->getSubscriber();
    $types = Mage::app()->getRequest()->getParam('types');

    $subscriber->setTypes($types);
    //$subscriber->save();
    return $this;
    }
}

Did i miss any steps or my approach is wrong and please advice me how can i check the process is in the relevant observer?
Is there any alternative solution add an extra field to newsletter_subscriber table?