NP m8! We are here to help each other. You may give me some rep-points if you want, you would have the dubious honor to be the first
Again, I'm not a die hard overclocker but had the same problems. It was very similar to what I experienced with this MB and CPU. Fortunately I have some overclock-memorymodules so I can push them a bit to be not that bottleneck where you are talking about. Buy some new ones and you will have one balanced machine.
About the extra videocard, I'm not a sli-fan. For that 10% of extra power I would buy a newer (ati is the fastest card atm, quality price ratio) graca. Then you have a energy efficient system, without the produce of much heat.
But if you want to calculate yourself how much power you will need, at the previous page is a link to a PSU calculator. Considering that stable would be the keyword in your choice for a new PSU.
Again no problem helping you out. There will be a point you may help me out with my problems