OC Amd 400+ Help Please!

Hi,

I recently upgraded my graphics card from an ati x1900 XT to a XFX ati 4850 HD. The problem is I think my CPU is holding my gpu back. I have no previous experience with CPU oc, and I noticed that people in this forum are quite knowledgeable in that regard so here I am! I would appreciate it if someone would guide me through the process by giving me sample values.

I'm posting my computer specs and uploading screenshots of my CPU-Z hardware info:

2 gigs of ram
http://imageshack.us/f/854/specsz.jpg/
by the way, the screenshot also has my idle computer temperatures
(from SpeedFan)

If there is anything else you need to know, please ask.