I think bottlenecking is really subject to what you're trying to do at the time. Some titles need a good CPU to enabled decent FPS at higher settings, other's seem to be happy on a fairly basic CPU as long s the GPU is up to the job. I'd say your average FPS these days seems to like good performance from both CPU and GPU, f you want to turn all the pretties on.
As others have said here, I think a small (initially) overclock once you have your uprated PSU might yield some extra performance. In my own experience, having a newer gen GPU with an older gen CPU, really benefits from a CPU overclock.
I saw this on my Q6600 when I upgraded from my 8800GT to my GTX 275, I needed that 3.6ghz OC to get the best out of the GPU. Moving on to a GTX 570, well the thing had an easy ride of it as the Q6600 even at 3.6ghz couldn't keep it fed in most of the titles I played. Going to a 2500k saw my 570's properly utilised at last.
Now, I have TWO 570's in SLI, my overclock of 4.6ghz on the 2500k is keeping them fed quite nicely.
So yes, get that new PSU, swat up on OC guides for your CPU and see what improvements you can achieve.
Best of luck.
Scoob.