oh sorry about that, my price range is anywhere from 100 to 300 dollars
for your price range, you are looking for a GTX 560 Ti or an HD 6950.
HD 6959: http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1241869&CatId=7005
GTX 560 ti: http://www.newegg.com/Product/Product.aspx?Item=N82E16814125401
Both of those GPUs are extremely capable of running the newest games on max graphics settings @ 1080p without lag. you also should make sure the rest of your system meets the requirements (mobo, psu, etc.)
While the specs of the HD card are higher than the nvidia card's, i personally prefer the GTX 560 ti, because it generally performs better in games and there is more headroom for overclocking. if you want to up your game ever further, you can get the GTX 560 ti 448 ( http://www.newegg.com/Product/Product.aspx?Item=N82E16814130738
), which is more powerful than both of the other cards. i personally would save the money for sli, but it is up to you
but make sure you meet all the requirements. have a good day