Where do you live?
In that price range the card you should be looking at is the HD 7850.Preferrably the 2GB version but the 1GB one isn't a lot slower (5%)
Or if the HD 7850 is out of your budget you should try finding a cheap GTX 560 Ti or a HD 6950.Both of them are really fast cards and you will not be dissapointed by their performance.