Check out this web site. I did side by side comparison of the of the q9550 vs. 2500k and then 460sli vs 560 ti sli. Sadly they didnt have the 465s but the 460 are close to it the 465 are just a little bit better.
CPU
http://www.anandtech.com/bench/Product/50?vs=288
GPU
http://www.anandtech.com/bench/Product/441?vs=314
Couple of issues with these comparison the gpu one doesnt use bf3 as a test platform but bf2 among other games. The cpu only compares using crysis, farcry2, l4d, and Fallout 3.
It seems like you will get a bigger performance gain from upgrading your GPU, but bf3 might utilize more cpu power than bf2 I dont know. Also, the performance of your 465 still seems descent based on those charts the lowest fps is 40 which is still good seems like the average is like 70. Also if you look on passmark your gpu is much more competitive with newer stuff then you cpu is with newer Cpus. All and all its a very hard question. Independent of one another the cpu is the weaker link and the 775 is out of date. From what I have read the Ivy bridge was a let down compared to te sandy bridge and the sandy bridge is a great budget build. For those reasons I would probably upgrade the cpu. You can always continue to save money and upgrade your gpu a little later by then maybe you could get a 580 or 680 and at that point your system would really sing. Plus the 2500 is great for overclocking and when benching you will for sure see some big improvements; however, in game and depending on what game will be a different story. Hope this helps good luck.
Just noticed johnners post and I would agree with that.