If you can wait then do so.
Your school should offer VIA MSDNAA a free copy of windows which should account for 150$ or so that won't come out of your budget.
I've seen various monitors on new egg drop as low as 100$ that were fairly nice monitors.
From there.. thats 1100$ for a netbook and desktop and it becomes a balancing act tbh.
I would wager your better off even having to buy a monitor with a netbook + desktop combo..
I wasted a lot of money on a gaming laptop that could play Oblivion and F.E.A.R. before crysis came out.
The truth is your not looking at a "hardcore pwnage desktop" but, your looking at a midrange desktop and relatively low end netbook. The upside is even if out of date these will all last a lot longer. Gaming laptops have pretty short lifespans.. All of that power in a relatively small form factor creates problems.. heating up/cooling down makes plastic brittle fast.. and when you look at gaming laptops.. thats what? 100C in the case? cools down.. heats up again off and on.. day in day out hour after hour. Then the more you actually move it around and bring it to class.. the more wear and tear that plastic suffers. So your laptop.. then becomes stationary to avoid more damage after a year or two.. You then start questioning how much a decent desktop will cost because, you realize your laptop may die at any time.
Or at least thats what happened to me.