AlienWare... Basically to an IT person that's just a code-name for 'overpriced, un-upgradable pile of silicon you'll need to replace in a year'.
Most of these specialty, "high performance" machines really aren't worth the money you dump into them initially when you start looking at the long term. For instance, a computer like this fits nicely into that budget you have, more than meets the specs for the game AND has upgradability in the processor, graphics card and drives that will extend the value of the purchase up to and probably beyond even 5 years: https://www.newegg.com/Product/Produ...82E16883221310
Do yourself a favor, if you don't know how to assemble a computer or change parts, find somewhere to learn, be it videos or classes or a friend. Learning how to swap out parts and upgrade on you own will not only make your rig what you want it to be but keep it running better longer.
P.S. Also, for me, if I buy a new graphics card for myself, I sell the old one mildly used for a discount on the store price, helps reduce the cost of upgrades a bit.