My personal advice would be to get a E8500 instead, specifically if gaming is the primary use for your machine. Even though its a dual core proc at right around the same speed as your current amd dual core...its MANY time faster. That DFI board would work fine with it too, and it would be about the same price or less.
I say go for an E8400 and OC it to like 3.5-3.8ghz. Dual cores usually beat quads in most games because they OC higher and most games only use 2 cores.
Honestly, I doubt you'd see much of a difference unless you like to play at fairly low settings, or low resolution...or are prepared to spend a lot of money. Otherwise, that CPU is still good enough. Hold out for moderately priced Nehalem systems.
consider yourself lucky that it runs at all. dozens of us are getting "game not available, try again later" for single and multi games, for a week now. steam support refuses to address this.
also, skip that mainboard, it has been discontinued and replaced with the lp dk p45 t2rs plus version that corrected its several problems. or the matx lp p45 jr board.