So these are the compments in my computer.

My components

WD 2500AAKS 250G 16M 7200rpm SATAII
LG Black Super-Multi DVDRW
Aopen Soundbox 300
Asus M2N-E nForce570 AM2 ATX MB
Sapphire x1950 XT 512MB GDDR3
Transcend 1GB DDR2-667
AMD Athlon 64 X2 5600+ 2.8GHz Socket AM2

Now i wanna dual boot Snow Leapord and Win 7.
Dont wanna break the bank with upgrading. I think my video card is about to go so i need to fix that.

So suggestions on how to upgrade to get a good machine running?