I'll be completely honest. $500 isn't going to get you much. I'm not going to dig through a foreign site, so here's what to look for:
CPU: X3 440
Mobo: Gigabyte GA-770TA-UD3 or ASRock 770 Extreme 3
RAM: 2x2 GB of 1333 mhz CAS Latency 7 sticks from any brand but OCZ
GPU: HD 5770 or HD 5750
HDD: Either Samsung Spinpoint F3 500 GB or Seagate 7200.12 500 GB (it's likely the 1 TB will be out of budget)
PSU: 550W from any of the following Antec, Corsair, Silverstone, SeaSonic, XFX or a 600W from OCZ.
I'm 90% sure that's out of budget. If it is, there really isn't much you can do to lower the cost besides dropping to a single 2 GB stick of RAM or getting a 2x1 GB kit.