That course requires you to build a small game as a work sample. Even a small game can take a while to make so keep that in mind. My girlfriend tried getting in that school for 2 years and it is very hard to get into it even with a good work sample. Have you looked into a plan B or C? As far as a portfolio goes, they most likely won't look at it (my girlfriend was told this from a speaker from there who visited her school). A PDF of your game and talking about the process it took to make it is all that is needed.