really..~
i always assumed you needed a good video card for WoW even though mine is pretty old it still might be worth checking out eh? and if all else fails i have a pretty badass toaster
WoW scales really nicely. You can run it just fine at the low end with fewer details, or you can make it gorgeous with a higher end machine. I find that the more important component to have is memory. I tried running it on an iMac with 512mb of RAM and it would choke a little bit in big cities, but was fine anywhere else. I think a 1gb or higher should be just fine.
You can always go to worldofwarcraft.com and download the free trial to test how your system handles it. (Beware, it's a LLLOOOONNNGGG download.)