What, are you kidding me? Wow is one of the easiest games out there to max. I'll make you a build when I get off work if nobody else has yet.
You could spend less than half that and max out wow, with FRAPs.
There are two main points here, though.
1) Even if you like nvidia, Radeon is blowing them out of the water, this round of cards.
2) Next gen technology will be coming out soon. It might be worth it to wait three months and get a 4th gen Intel chip with a 700 or 8k series GPU. Actually no, it would be VERY worth it.
There really isnt anything better than a i5-2400 unless you want to overclock, which would most likely require a new motherboard and stuff.
What power supply are you running?
And how can you not max it on this setup?
I can max it but my FPS go to 25fps in normal stances, and goes to 5 fps in LFR so no, my pc cant handle mist of pandaria in ultra. BTW MoP requires much much more stuff than cataclysm, i was able to play ultra in 50-60 fps all times in cata (except LFR) but MoP im playing almost in the lowest settings
I think ill wait as dark sable is saying, and get the newest *** to be future proof