I just went out and got myself two 7770's, then realized my phenom II x4 965 wasn't as happy about it as I was. I'm in need of a good upgrade suggestion, not only for this current setup but also something that could handle high end cards in crossfire.
phenom II x4 965 3.4 Denab
Asus M5A99X Evo Motherboard
Corsair GS700 power supply
Ripjaw 8GB 1600 Ram
HAF 922 Case
2x XFX 7770's
there really isn't unless you go intel. the only upgrade you could really do is to a fx-8150 or something like that, which won't help much at all. you would have to get a new motherboard and a i5 2500k or something like that.
7770's in crossfire setup aren't a good idea. One strong card would be better. Like a 7850/70. If you can still return them, I recommend doing it.
As for the CPU, overclock it and it should be running fine.
Again, pretty sure that the issues you might have aren't CPU related, but because you paired 7770's. Which shouldn't be bottleneck'ed by a 965, even at stock speed.
Your first question should have been "Will crossfire 7770s be good?" to which the answer would have been what he said As a rule of thumb don't get two weaker GPUs over one strong one. Ever. Of course there are exceptions but it's a good rule.