Upgrading and semi-old desktop.... ?

i have the Gateway 820 GM i have upgraded the power supply to a 500 WAT, and the graphics card to a 7600 GT.....my question is will the motherboard be able to fit a dual core and or will it be able to crossfire the 7600 GT............also would more a extra gig of ram help? Processor Intel Pentium 4 3 GHz Chipset Intel 915 G Installed Memory 1 GB (DDR SDRAM) i plan on buying the 8800 GTS320 MB when it drops to around 150$-200$ and upgrading the processor to the Intel Core 2 Duo E6320Upgrading and semi-old desktop.... ?
i want to be able to play gameslike Crysis, Unreal Tournament3, andotherson high in DX 10 for at least 2-3 years without having to upgrade, if im paying 500$ it should last me at least as longs as a consle one other thing why can my 7600 GT outpreform my 360 Visually Wise in Prey?Upgrading and semi-old desktop.... ?
What brand and how many amps are on the +12v rail? And yea an extra gig will help.
conroe and this the socket type LGA 775 is that wat u needed?
I think that mobo supports only Pentium 4 and Celeron D.

You need at last 945 chipset for C2D
[QUOTE=''LouieV13'']What brand and how many amps are on the +12v rail? And yea an extra gig will help.[/QUOTE]

I meant the psu im a noob when it comes to intel cpus... just 500w wont help cause it could have 14amps...