What chip to look for?

[baronvongogo]

ok you could buy this cpu:

http://www.overclockers.co.uk/acatalog/Socket_A.html

the bottom 1 but im not sure how much of an increase if any it would be.

and upgrade ram if possible

http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=17813

think that will work with your motherboard but it depends on if you already have 1 stick of 512mb or are using 2 sticks of 256mb

your motherboard has 2 different ram slots for 2 different pins not sure if you can use 4 rams if 2 are different pins than the others.