Hi. I play dirt 2 in minimum settings, at 800x600 on my 15" screen. I want to play dirt 3, at ultra settings at 1024x768. What is the minimum graphics card that i can get that will work for this? My computer is Microsoft windows xp professional version 2002 Service pack 2 AMD athlon(tm) II x4 620 2.62GHZ 2.5GB RAM. And no graphics card yet.