Your graphics chip is going to probably be your most major issue with running all of Win7. Looks like you have a ATI Radeon X300 which has known driver computability issues with Win 7. I would look into this a little more if I were you before pulling the trigger here. It wasn't exactly clear to me but it looks like people can run win7 just not Aero. Although i found one post from someone claiming to have solved that (http://it-nthusiast.blogspot.com/2009/12/ati-radeon-x300-aero-on-windows-7vista.html).
KINGSTON 2048MB (2x1024MB) 533MHZ DDR2 DIMM NON-ECC CL4 (KIT OF 2)