p4 2.8 800fsb HT
1gig ddr ram
nvidia 6800 128mb gpu

The game runs kind of slow on my computer. Im not sure what i should upgrade to make it faster. any suggestions???

an upgrade will do you much good
1 the processor, is old but fairly OK
2 memory make sure you have 2 gig and preferrable in dual channel settings (though I doubt that works with a single core processor)
3 graphic card, almost anything is better but get a card with at least 256 MB DDR3 memory (geforce 7600 GT and better or 8800 GTS if you can afford it)