There are only so many PSUs:
Can run my computer, won't fry my computer.
Can run my computer, might fry my computer.
Not enough wattage, wont' fry my computer.
Not enough wattage, might fry my computer.
All other variations are minor. There's not really one 'suitable for overclocking'.
Currently you have option #2.
I dunno how many watts the i7-920 can draw heavily overclocked, but pretty most 1-gpu systems will be fine with a quality 450w or so unit. Go to the power supplies section, download Phaedrus' power calculator, estimate what components you'll have, and it'll give you a list of the first type of PSU.
Personally, it looks like you're good to go with maybe a new video card for games or a PSU for peace of mind, but it looks like you should have a competent computer that runs everything you want it to run right now. Are you having some sort of bad performance issue? Edit: Ah, read more closely above. Yeah, for BF3 and Skyrim the only upgrade you can do aside from spending some serious cash is a new video card. Depends on how high you want the resolution. If I were you, I'd be looking at the 560Ti, 7850, or 7870 depending on budget and desire to move from high settings to max settings. For less budget, suck it up and lower image quality.
As for PSU, it's fairly cheap to get something like this (w/ promo code EMCYTZT1327 , also, more than enough quality power for any 1-gpu setup ):
or shop from the list from Phaedrus' calculator trying to find something cheap that's still in category #1.Edited by MisterFred - 3/20/12 at 6:06pm