need lots of help deciding what to do with this pc

[adam8xz]

i dont know much about hardware and im worried im not getting the best experience with games.

amd athlon 64 x2 4200+
ATI Radeon HD 3870 X2
4GB ram
the mother board is Asus M3A32-MVP Deluxe (2 PCI, 4 PCI-E x16, 4 DDR2 DIMM, Audio, Gigabit LAN, IEEE-1394)

i just wanna know if any components are holding it back and if i can make any improvements for a couple hundred dollars(minus the money i would get for selling the old parts).
thx

 

[Jagged.Edge]

What about your PSU?

 

[adam8xz]

123/230v 520w

 

[MyGodAL3X]

what is your budget, if you give a budget there are some awesome deal finders that will get you the best parts for your price

 

[adam8xz]

well i was more looking if there is anything that i need to upgrade to make full use of the rest of the computer so i was thinking no more than 1 new cpu or graphics card because i dont have the money rate now to spend more than a couple hundred dollars but if i replace a part i also get to sell it so... i guess less than 200 dollars+the resell value of the replaced part would be my buget