We arent too big on prebuilts around here, since building your own isnt hard, and will get you better parts for the same price so i definitely suggest considering it. If you are willing to try it(its not hard i promise!) head over to the Systems forum and make a post using the template below, and see if we cant beat those prebuilts. http://www.tomshardware.com/forum/261222-31-build-advic...
I agree with hunter, it's not as difficult as you might think. I'm actually building for my very first time and learning as I go along, but once I've gathered all the parts I feel pretty confident in assembling it myself.
And don't worry! The people here at Tom's are very helpful so you'll be safe
GPU: http://www.newegg.com/Product/Product.aspx?item=N82E168... ( You can swap this card and make it a little cheaper, the reason for this is I like EYEFINITY, If you're not intrested in a smooth eyefinity experience there is other DX11 Cards. Total war games wont need something this good, but I like to future proof.)
RAM: http://www.newegg.com/Product/Product.aspx?item=N82E168... ( This is a good price, there are lots of others though, this is not the only option, but it's a good one. Only 4gigs, but not to much more is needed right now, and you can always upgrade in the future, 4 gigs is a good starting point though for your budget.)