What part of my brothers computer should be upgraded?

[Mobius]

My brother has my old computer, and he wants to upgrade it (It's a few years old now) as it struggles with Battle for Middle Earth, and he wants to buy Caesar 4 at the end of the month. I could recommend him new components, but I don't know what cpu etc is valid for his motherboard, because there are restrictions aren't there? He sent me his DXDIAG thing anyway, so here are his specs. (I hope this is all thats necessary! I have the dxdiag if you need anymore infooooo)

Mobo - ASUSTeK A7N8X-X
CPU: AMD Athlon, MMX, 3DNow, ~1.1GHz
Ram - 1gb
Gfx - Radeon 9700pro (128mb)

He can't really afford a new system, and doesn't really play enough to warrant one but if there is a part that can be upgraded to improve performance (I think the CPU, probably?) then that would be cool. Cheerski!

 

[WPKenny]

New processor tbh. I mean the whole lot should go but if it's got to be one thing I'd say the processor and then the gfx card. Both together if you got the funds but good luck finding a AthlonXP anywhere but Ebay.

 

[Tombha]

a pc is all about style imo.. buy a new cabinet!