Well, with your GPU and CPU isn't a good option that you install this in a AM2+ mobo with DDR2.
You can get a new mobo and DDR3:
RAM: G.Skill 4GB 1333 CL7
$104.99 with free shipping.
$74.99 after rebate and free shipping.
Total: $ 179.98 after rebates and both with free shipping.
Is a good upgrade option for you.