You'll be fine. Of course, with any GPU a faster CPU will help it perform even better, that is a no brainer, but it will still perform well. Just overclock that 930 as far as it can go and enjoy the GTX.
Some games are really CPU-bound, so even with a 8800GTX, you might get not so good framerates because of the CPU. But your CPU is still not that old or slow, so don't worry too much about that. In general the 8800GTX will serve you very well, and you'll get excellent performance in most games.
Since you plan to upgrade the whole thing, you'll be glad you have the 8800GTX to begin with.