Haha! Well: you'll need a new Processor, a new Motherboard, a new Graphics Card (you'll hate your 8MB one with a newer processor, buts it not required), new RAM, new Heatsink, and a new Power Supply cause you'll need more power.
Basically, you'll need a whole new computer. It would be cheaper to go out a buy a second hand one than try and find all of these bits and buy them.
Look in in the Friday Ad.
A Knight is sworn to Honour. His heart knows only Virtue. His blade defends the helpless. His might upholds the Weak. His word speaks only truth. His wrath undoes the Wicked.