You will have to experiment and test on your own. I'm not trying to be mean, it's just that no 2 pieces of hardware are the same, not do they react to OC'ing the same. I would not recommend simply using someone else's numbers right off the bat - dangerous
There is a thread floating around here about a member that can't get his/her 7600GT to OC - sometimes it's just bad luck.
Just make sure that you do not allow the card to get too hot. Once you have an OC that is stable, monitor the temps for a few days to make sure that there are no anamolous problems.
Try Coolbits and use the "find optimal" setting, then go from there. When OC'ing manually, increase by 5Mhz at a time, and do the clock alone, then the Memory alone. Once you have the limits on each, drop it about 5Mhz on each and try it out.