Need Build Advice

I NEED to build a decent gaming computer So far i have collected the following WORKING parts to use, nzxt source 210, celeron g555, ecs motherboard, 2gb ddr3 1600, 6gb tripple channel memory for 900 series i7's, dell 450w psu, wd 650 gb hdd, and some dvd writer.So my question is, What is my best option and cheapest for gaming? I Have an EXTREMELY low budget and get most of my parts from a computer recycling center. so I imagine I could get a scrap athlon x2 and if its a complete fucking miracle an athlon x4. so anyway why dont all of you yell at me untill I do something. thanks

How low of a budget?

Sell it all for money.  The gaming performance will be horrid with that stuff.  Sell it, save some money, and build one with recent tech.

budget is as low as possible, No i cant sell, im 14 and have no way of mailing any of this anyway so what you pick should be like under 400 and using existing parts