yeah, Ct1615 link is good but please tell us wat do u plan to do with ur new videocard?
if its gaming(most likely LOL), then tell us wat u plan to play...also please mention ur ENTIRE computer's components including processor(Intel Pentium, core 2 duo, athlon etc.), RAM and also ur MONITOR's width, so that we can determine which card is really right for you if u need to upgrade sumthing else
If u don't know how to tell your PC's components go
Start==>Run==>type 'Dxdiag' then hit ENTER and then hit NO on the certificate error thingy then click on 'Save all Information' then open the file then copy all the contents and paste it here.
The instructions shud be pretty similar to Vista and Windows 7, just click on Start menu then type 'Dxdiag' in the search bar and hit enter