If you're not comfortable building a PC you can always use: http://www.newegg.com/Product/Product.aspx?Item=N82E16883109040
With an HD 5670 for ~$500 shipped.
Alternatively you can use
http://www.techreport.com/articles.x/18747/2
For a complete good list of components.
ORRRRR
You can stick an HD 5670 in now: $93
http://www.newegg.com/Product/Product.aspx?Item=N82E16814161319&cm_re=hd_5670-_-14-161-319-_-Product
Then decide later if you want to upgrade because when you do you can reuse the card and do the upgrade in easier steps.
Tease.







