Video card for my Dell XPS 400

Hey guys, My question is what type of video card can i get that will play Diablo 3 decently... theses are the supported graphic cards http://us.battle.net/support/en/article/D3supportedvideo.  I don't have the money for a new computer so i am kinda stuck with my dell XPS 400. My service tag number is <ADMIN NOTE: Service tag removed per privacy policy> so you can get an idea of what type it is. It came with a Radeon x1300 and i already upgraded the power supply from 375 to 400... nothing big. And while im here i guess i should ask this question also... My DVD/CD drivers don't work and i looked to see if i had the drivers installed but i don't see them. So i don't think its the dvd/cd player itself, where can i find the drivers to install it for my specific computer?

Thanks for the help,

DJ