Thinking about getting a new PC for Live

Ez guys am currently thinking about getting a PC for running Live on and am looking to spend around £400-500. Currently I use a Dell Inspiron 6400 Laptop (T2060 1.6ghz processor with 2gb ram) for Live. It does the job in that I can make tracks but it has it limitations as basically I can run about say 5/6 audio channels and a few synths and a few fxs at which point it says 'enough is enough'.

What kinda performance can I expect if I get a PC by comparison as I'm guessing I should get say at least 2/3 times the power of that now right?

Thoughts welcome.

I use a core2duo 2.3ghz with 4 gigs of ram and i never peak 15% cpu, that being sad, I don't make the most complex music in the universe.