Help with parts for an old Dell Workstation

Hey Tek syndicate team.

I am currently upgrading an old Dell Workstation 650 series.  This thing has 1gb of ddr1 ram (4 sticks of 235mb i think) one Xeon socket 604 CPU at 3.06.  For graphics I have a Nvidia Quadro Fx 1000 (AGP). I have a matched pair of cpus coming for the system to make it a dual core. I am wondering what up grades i can do to this thing, it would be nice to have a better graphics, thats what i need help with is there a graphics card that is better than an HD4670. Or Is it even worth upgrading, should i just sell the Pc, i am currently using at as a music server so it works pretty well as that it can run doom as well as any low graphic game.

Thanks in advance,

Hax

More ram; you can get ddr1 cheaply (ex. http://www.ebay.com/itm/NEW-HIGH-Density-Lots-of-4X1GB-PC3200-400Mhz-184PIN-DDR1-400-Desktop-memory-RAM-/151364250166?pt=US_Memory_RAM_&hash=item233e032a36 )

as for gpu's 4670 was last and best of all AGP cards; and from nvidia its NV 7950 GT

Since all those parts are extremely cheap you can as well as keep it; though new pc will be much faster than this.

I have a really pretty nice gaming PC. I just got this computer for free from an uncles shop. Thanks for the help.