It actually might still bottleneck, even with that high clock speed. Bulldozer has a lot of problems, and overclocking only alleviated some of those. You also only have two modules on that chip, meaning you have 4 integer cores, but only two Floating Point Units that have to be shared, which will probably negatively effect gaming performance.
You can get the two 660s, but you may find yourself in a position where you'll need a CPU upgrade as well. I hope your motherboard supports Piledriver.