Need a new PC !!!

[xes]

Hey there,
Im thinking of upgrading my system and im unsure on what to go for.A Mac G5 would be great ( in my dreams) but totally out of my price range,Pro tools M-powered works fine on the pc I have at the moment but I want be comfortable dealing with big sessions,any ideas?
Here my specs at the moment.

Asus X series P5VDC-X motherboard
1gb ram
250gb Hard drive x 2
Nvadia dual graphics card
delta 1010lt