Sorry for being unclear, I was talking volts. What are your current temps (and also include what voltage thats at)? Your power supply should not be a problem at all; 400 watts should be enough to handle overvolting the core. You might however want to watch your other voltages ( 5 volt line, 12 volt line, etc) while your raising the core just to be sure they are staying in spec. If they go too far below, you might start having random reboots. I don't think it will be a problem. Now, if it was my computer, this is what I would do:
First, run Prime95 for as long as possible, preferably 24 hours or more. If you can get through that with no errors, you're stable. Unless you wish to overclock more, leave the voltage.
Now, lets assume that either its not stable enough or that we want to oc a bit more.
Raise the FSB by 2 -3 mhz, if you want to overclock more. Repeat the Prime95 test. If its not stable, raise the voltage in the BIOS in the smallest increments possible (.025). Each time the voltage is raised, repeat the Prime 95 test. Also, check your temps and make sure they are reasonable. Personally, I would be very uncomfortable over 60C.
Now, as far as I know, the A7V333 puts out slighly more voltage than what is selected in BIOS. For example, mine is set for 1.75 volts, but pc probe reads VCore at about 1.79. Someone on this board once said that they had measured the VCore with a multimeter, and the higher one reported by pc probe is correct. Just something to keep in mind.
The most important thing is to be careful. If your not sure about something, don't do it. It's better to have a slightly slower computer than a broken one. BTW, you're welcome.