Need help with my asus eah5770

Hello I'm just wondering a couple things.
1. What is the max temperature I shouldn't go over when overclocking?
2. What the max vcore for this chip?

My whole plan after o/Cing my cpu was to upgrade to a 7770 but unexpected money flow problems happened and I'm trying to wring every last MHz out of my video card any input is greatly appreciated

For really high overclocks I would say a temperature ceiling of 80*c is a reasonable limit, especially if you are overvolting.

If stock is ~1.1V, I wouldn't go over 1.2-1.3, I'm not sure how safe that is. You certainly won't gain many fps though, so be careful, a slow card is better than no card

+1, you are better off just trying to max out your overclock with stock vcore. The max I would personally try pushing it would be 0.5-0.75v above stock. However, I do not have much experience with that particular card so someone may be able to advise you further.