I personally wouldn't buy a ram kit, I'd look more toward CPU at that resolution. I actually just got done playing some BFBC2, at 1680x1050, everything on high, I averaged 48fps.
Q6600@3.42, 8800GTX, 2x1 Corsair PC26400 - 4-4-4-12.
Might be an idea to look at, as that game does recommend a quad, and at that low of a resolution, your 8800GT should be able to handle it.
EDIT: Nevermind. Drop a 955 in there and be done with it. It will transfer over to a DDR3 build, and is one of the best AMD's got right now.