The page may be temporarily unavailable or may no longer exist. There are a few things you can try:
Nice error 404 on that link. I ripped the SKU out of the URL (thank you, BB!). This rig? http://www.bestbuy.com/site/olspage.jsp;jsessionid=7F552EC8D80BA008640EE4AB8B4B35EF.bbolsp-app06-48?_dyncharset=ISO-8859-1&_dynSessConf=585266171416364107&id=pcat17071&type=page&st=9697488&sc=Global&cp=1&nrp=15&sp=&qp=&list=n&iht=y&usc=All+Categories&ks=960
Configure it with the GTX 260 if you want the GPU to be at least as powerful as the one you've selected. With that upgrade, you're looking at $1429. But that includes monitor, keyboard, mouse, etc. Shipping is free. Depending on your state, you may be able to not pay sales tax up front.
Otherwise, just wait for the sales. You just missed a 2-day sale on Alienware (made by Dell) desktop rigs at 20% off from their outlet store, which could have gotten you a decent rig.
Nice page not found error on your link to the dell site too lol.
You said that the one you linked was too expensive. I can't really suggest much without you telling me what isn't too expensive. Also, are you limited to specific stores? Are you willing to order online?
The problem with most prebuilt computers from retailers is that unless you buy a computer with a high end CPU like the i7 (which you wouldn't need) the computer does not come with a decent graphics card, even though it is labelled as a "gaming" computer. I'll let you know if I find something on the bestbuy site.
I'm not sure but I don't believe you can link to something once you have configured it. Dunno. It seems to cut off half the link when I click. Doesn't matter though as long as the OP can click on the link.