This is about the next step for Graphic cards is a HD 6770 it is ATI card here is a link
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150540
Now your windows 7 is around 100.00 to 120.00 depending where you buy it. Both Items together are over your budget. Even if you get the same card you are still looking close to 50.00 to 80.00 for it. I know this isn't much to go on but it is a little bit better than what you have.
The reason I chose the ATI card They have more cards to play around with than Nvidia does on the lower end. I hope this helps a little