Question that I need help with

As prozac says, those won't fit together.

the cheapest CPU that newegg has that'll fit that board is a A64 3000+. Costs quite a bit more though.

Alternatively, stick with the original CPU and get this motherboard instead. It's only $1 more.

I have no idea about the difference in performance between the onboard Gfx (the Nv 6100 on the board you listed Vs the Ati one), but either won't be that good for modern games anyway...