I know this thread is a tad stale, but I was reading your other thread and came across this one. Will post both places.
For most games right now, having a faster quad core cpu(or one that can do at least 3-4 threads) is more important than a slower hexacore(or octacore). True the ps4 ( and likely the next xbox) will have 8 core amd processors, but those are based on the jaguar core(an update to the ultra portable bobcat core) and not based on bulldozer or piledriver. The stars architecture(a refinement of the K8 of athlon 64/x2 of old) has higher IPC. If you get something like a phenom II x4 970(BE) for around 100 and a decent cpu cooler like a cooler master hyper tx3, you can overclock to 4ghz+ on your mobo to help eliminate any potential cpu bottlenecks that might stymie the performance of a new gpu. Then, you go for a bit less powerful gpu than a hd7970(like a hd7870xt). The combined pricing of new cpu, cooler and hd7870xt will be about the same as a hd7970 alone(about 360 after rebate). I'm just going to figure you have a power supply that is up to the task and that your case can fit a larger size graphics card.
Edit: a 2.9 ghz amd cpu(3.2 turbo) won't cut it for BF3 MP(the main reason for getting that game).