Making changes to better system AMD ddr3

Hi I was rebuilding my system the other day and hadn't gotten ram yet and old psu died so I sent my dad out to get ram only specified to him 4gb ddr3, he got me 4GB DDR3 Viper and 680Watt psu. My friends told me my AMD x2 240 won't be any good with ram above 1333mhz. Is this true? I was building this system to just casually play DOD and CS till I finish school which is about 3 months away and my PC died. Games are old so will any cheap graphic card do? Since I already have ram should I change my processor or could I just start overclock and hope I don't blow this one? Current Specs are: MA770T UD3P(New) AMD x2 240 4GB DDR3 1600 Viper(New) 500GB HD 1gb 9400GT(off a friend) P.S. I'm got about another 200 at most to spend

Yea its generic, was very cheap, i'm gonna transfer the psu over to my other rig(word editting p4) once i get another psu, probably won't be for a while.
I'm holding out on gpu for now since its free and I don't really need to game, dod and cs are all I'm really playing for now with exams around the corner, maybe xmas or new year will bring some nice gpu's at decent prices.
OK so ram's fine, but would it benefit from upgrading on cpu or wait to later and upgrade together with graphics and psu.(Probably replace psu if I change anything on system now)