WAIT STOP! You said this http://www.asus.com/Motherboards/P5ND/ ? DO NOT BOTHER WITH THE GPU, you need a totally new PC! This board is over 5 years old and supports P4 CPUs! This isn't even supported for ages now.
You need to look at a whole system replacement, and it can be done cheap if all you want is WoW playability. Pick up a i3 Desktop at Walmart ($249), I do NOT think the PSU you have (since how old it is) has all the right connectors for MODERN systems and GPUs, so get a 500-600W ($90) to replace the generic one in the Walmart i3, then spend the rest of the money on a decent video card (Nvidia 7xx or AMD Rx) around $149-$499 depending on which. Done.