Another Budget WoW Cata Machine

Dear Community,

I have been patiently attempting to build a budget machine to run WoW Cataclysm well, and am looking for some advice. I currently have an old Gateway mini-tower that I have put some upgrades in and would like to keep some of the pieces and use them for the new build. I would like to play WoW Cata (prefferably in window-mode, so I can alt-tab to the Internet and Zune media player (on a 2nd monitor). As for the resolution I would like to play at 1920x1080 at reasonable 60 fps, Ultra settings would be nice but being able to run it at 60 fps period would be nice being as I'm used to play at less than 30 fps on my old Intel P4. I will list the components I own already and I am hoping for someone to recommend a CPU/Motherboard/Memory/Graphics Card solution to go w/ it. If any of the components are unsuitable, I would like recommendations for them as well. Fairly open to criticism. Thanks in advance! Oh and random note, I would prefer to not have an onboard audio solution, past experiences have been faulty... and a quad-core type CPU, no real preference which ATI/Nvidia or Intel/AMD, just what will do best for the money. I would like to not spend more than another $400-500 if i can help it, not including a better graphics card which I may buy at a later date. Anyhow, thanks for the read. If you need more information, as I've likely forgotten something, please ask me!

Main Monitor = acer H213H 21.5" Wide LCD Monitor

Secondary Monitor = Dell 1908FP 19" LCD

Graphics Card = XFX ATI Radeon HD 4350 1GB GDDR2 - this was a bad idea, and I would like to replace it w/ something that works better, the power supply I will list has a PCI-E connector so that won't be a problem on a new card.

PSU = Corsair GS700 (700watt)

Case = Antec Three Hundred Versatile Mini Tower