Attack this from the outside.
Use Google's filtering capabilities.
For example, let's say I wanted to search for videos by user "MyAbridged" posted in August, 2012.
I search for myabridged site:youtube.com
to get videos by that user.
![enter image description here](https://i.stack.imgur.com/DuOg5.png)
Then click Search Tools and you will see Any Time come up as an option.
![enter image description here](https://i.stack.imgur.com/vaxsQ.png)
Finally, click Any Time, choose Custom Range, and select the time frame you want to restrict your search to.
![enter image description here](https://i.stack.imgur.com/1XVzQ.png)
Complete your search and you now have all the videos posted by that user in that time frame.
Example search: myabridged site:youtube.com between Aug 1, 2012 and Aug 31, 2012
Note that this search technically searches for any pages within Youtube that mention the name "MyAbridged" anywhere in the page, so it will actually return back more than just their videos, but it will get you where you need to go
Best Answer
Select all the videos from the video manager. Click edit. Then click title. Then you will see a screen that can add a title prefix to front or back. Check the screenshot below for reference which I did from my account. Click update after doing the changes.