Things we need from you before we can give you any reasonable ideas for upgrades (aside from the BUY A NEW SYSTEM NOOB LOL):
  1. What is in your system now? (HDD, Graphics, RAM, CPU, motherboard)
  2. How many copies of WoW are you trying to run?
  3. What do you have your WoW's graphics settings at? (resolution, details/effects, etc.)