That sounds like ONE Pentium 4 running Hyperthreading.
What you want is an upgrade. AGP and Pentium 4's are ancient now. Conroe will be out by the 18th, and if you are looking for a budget system, Am2 semprons are already out. Both systems can be built for under 1000 dollars.
If you want more details, please say so, I can link you to some parts. I'm sure any other members would also help.
G. Skill 4GB(2x2GB) DDR800
eVGA 8800GTS 320MB
super pi: 1m=20s