Upgrading Computer need tips

Hello, i have been coming to Toms hardware for a while but i have never posted before on the forums, the reason i am posting is because i am looking to upgrade my current system but i am on a budget of £120, at the moment my computer specs our,

AMD Athlon XP 3000 2.2ghz
ATi x1650 pro 512mb AGP
1 GB DDR2 RAM


I am looking to upgrade to dual core, i have been looking to only upgrade the motherboard and the CPU, the processor and motherboard that i have been interested in getting for my upgrade our these:

Athlon 64 X2 7750+ (2.7Ghz) Black Ed AM2
GIGABYTE GA-MA69G-S3H AM2 AMD 690G


i will be upgrading the gpu a few weeks later, the upgrade is focused on gaming
i am looking for anythink anyone has to comment on my upgrade and suggestions are welcome as long as they remain in my budget.

this is my first time duel core computer and am not familier with all of the chips that our out at the moment, i have looked at e6600 but it would leave me out of my budget as i would also have to change the motherboard as well,

thanks!