Going through Amazon for each of those
280 = processor
50 = ram
75 = HDD
220 = Graphics
=675 without the copy of windows. You might be able to get slightly lower for a few of those (16 gigs of equally fast ram is not a lot more and I am willing to be alienware will have dumped two 4 gig sticks in there) if you go around a lot of sites, look for bundle discounts and maybe drop an extra 20 here and there for something even nicer. It looks pretty respectable as far as the price/performance line goes though (as in you probably will have to drop a fair bit more to do a lot more damage).
330 or so for the case, motherboard and PSU.
Call the case 80 though you could shave a bit off there.
250 left
PSU probably another 80
170 left
That handily does most motherboards (SLI/CrossFire capable boards even though you probably do not want one will likely eat that up) and a DVD drive if you decide you want one of those.
This is still missing windows and system builder versions of various OSes are not the cheapest (over 100 USD) for a proper version and I would be hesitant to throw that cheap a motherboard at your gaming rig. It might still happen though.
Alienware have legendary warranties as well (do check to see how hard it is to act upon if you plan to have this in Turkey) so that might be a perk, alienware (some of their laptops aside) are not all that they once were though and this looks to be something of a "buy it to have the badge" type model. You say you have not built before and if you do not have someone that knows that game with you for ever step of it then it is probably best to not go for it. If they throw in a nice keyboard, mouse or any form of monitor then go them.
Personally I build machines unless I need to fit an office out with them (in which case having someone I can call up, have it all sorted for me and drop it back off is enough of a perk to go for it) but it has not been a "this will get you either a far cheaper or a far higher performance" machine for many years now, the best you can hope for is you know the parts going into it and so you can be sure they are nice (the amount of cheap network cards I have had to replace in Dell machines over the years.....).
As Ryupower said though you do not need to drop a fortune to play things as well or far better than the current consoles. This might change again when the PS4/720 drop as I am not sure whether the Wii U will hold things back here but that is not such a problem as they are not likely to be out and swinging at full capacity for quite some time.