You can buy individual liquid cooling componets at the websites I listed.
You would be better off to save up for the 8800GTS (roughly $320 CDN) or get a ATi X1950XT. OCZ, Crucial, Corsair, or Mushkin DDR2 667 or DDR2 800 2gig dual channel memory kits will be OK.
You could get the E6750 instead of the E6850 and use the money saved on a better video card, your game performance will be better with the e6750/8800gts combo than with the e6850/8600gts.
or some other online retailer, eBay is not the best or cheapest place to buy new PC componets.