I have a HP A6000N PC. It currently has 1GB RAM and a AMD Athlon 64 X 2 Duo Core Processor 4200 + 2.20GHZ CPU. I am not sure of the graphics card. It has what it came with. What can I upgrade it to with current mother board as far as RAM what so I need and what is bestt CPU and graphics I can put in it without breaking bank???