I am a big fan of newegg.com, so see if you can find some deals on that site also.
Man, it's been ages since seeing a Nforce 4 motherboard. Socket 939 was just under AM2.
Bus speeds on the ram/cpu are limited so the lag might be quite bad... It is better to piece something better with at least 4gb ram. If you're looking to save, buy AMD. Intel is pricy for their stuff, but if you have the money for it, go intel. Believe I pieced a motherboard,triple core cpu, and 8gb ram for like $150 over at newegg, and that would boost game speed considerably.
Either way, good luck!