Everybody's settings will be different as no two cards are the same. Just stay on stock voltages take the core clock up by about 100 Mhz at a time, running a benchmark after each, until your clock is too high and the computer shuts off. Then you know you hit the limit, and you can go down in increments of 50Mhz and benchmark with a stress tester until you find a stable clock speed.

As for your memory clocks, just add 200 Mhz or so to it. You won't see much performance gain there.