By going with low brand name power supplies you want to get a little over 500w so you'll have more of a chance to get 500w.
Well i just found this one, it look ok? http://www.amazon.com/Cooler-Master-eXtreme-Supply-RS50...
Im running a inspiron 530 case, the powe supply i have in there right now is *model number PS-6351-2 350 power supply.
Will this cooler master plug into the motherboard a amd phenom ii 4x 965, 7850 graphics card and will it fit my case
It will work as the connectors are standard across motherboards and psu, unless you bought a specific system with its own motherboard design (I remember seeing HP with weird motherboard connector design)