Yeah your choices are very very limited.
A) go with the Alienware 13 and get possibly stonewalled by some games that need more CPU power.
B) go with the bigger 15" laptops and live with playing at lower settings (such as medium setting and forcing res to 1280x720)
C) Buy a cheap laptop, a 20" monitor, and a PS4 and call it a day.
Ultimately, I like C because you don't have to worry about how good your laptop is and just use it for notes/classes/movies/the occasional web surfing when prof rambles. AND the PS4 will probably play games for years to come and probably better than the Alienware. But thats just an option.