all those prices are american we pay the conversion plus another 10% ontop and usually a bit more especially with g cards. here are a list of good sites'
ITSdirect – Buy Systems & Parts at Australia's Only Service Based Online Computer Superstore! - everything
Mwave Australia: Buy & Save in more than one way at Mwave! - "
PC Case Gear, Quality case accessories and components - cases/cooling
Forwarding to the Online Shop! - cooling
PC Maniacs - everything
for about $500 the best you could get would be something along the lines of this; (from itsdirect.com.au)
AMD Athlon X2 4200+ Socket AM2 CPU (ADO4200DOBOX Retail Boxed) $73.21
Antec NSK 4000 Case (Black, No PSU) $65.00
Cooler Master eXtreme Power 430W Power Supply Unit $66.00
Corsair 1GB DDR2 667 (PC5300 - VS1GB667D2) Value Select RAM Module $30.70
MSI K9A2GM-F V2 AMD 780 Chipset Socket AM2 Motherboard $87.00
Pioneer DVD115 DVD Writer (IDE, Black, includes Nero) $37.40
Samsung 250GB SATA II Hard Drive 8mb Cache 7200RPM (HD250HJ) $72.70
XpertVision nVidia Geforce 8500GT 256mb PCI Express Graphics Card $61.60
Freight: $50.00
Total: $543.60