What video card can help me

[Lucy.T.Morris]

I'm looking to upgrade my video card so I can use the new shadowing system, among other things. Currently, if I have it set to even the lowest real-time setting, then I get these weird artifacts on screen; It's basically an overhead map of the shadows, allowing me to see things that are off camera/behind me. Also, bonus points if I can have 2x (or higher) multi-sampling. My average framerate is 23fps, with everything except for object distance, spell effects, and weather intensity set to low.