First of all things like sensor size and megapixels do not automatically create better images - a lot has to do with the quality of the engineering.
The issue you are having is with the lens...it is not fixed aperture which means it is going to get darker as you zoom in. Sony does sell a fixed aperture wide angle lens:
http://store.sony.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10...
It's 16mm and 2.8 which is fairly fast - helpful for those narrow depth of field shots. That's about $250 and would be a much cheaper solution than buying the T2i - now I'm a big fan of the T2i, that's the only camera I use right now, but still it might be worth trying this cheaper alternative out first - if later you get the T2i you can keep the Sony as your "B" camera for either multicam shoots or as a backup unit.
Steve Crow
Crow Digital Media
http://www.CrowDigitalMedia.com
