sheesh - first things first, don't quit one job unless you have another!

seriously, unless you can afford it.
i SO understand what you're talking about! back home on the east coast i NEVER once had a job i enjoyed. i would get so furious with just going in everyday and dealing with the same stagnant garbage, nothing changing, exact same everyday... it felt like "what's the point?". that's when i made a change too.
everybody kinda has there own way they got into the industry, so there's certainly no set way to do it. it sounds like you already made a pretty good impression on one of the companies. thats a great start! maybe they'll remember you? a demo reel would certainly be a huge help, but i understand your concern that there won't be much on it. at the beginning of a career, your demo reel tends to be more important. after you've been doing it a while, at least in movies, your credit list kinda does the work of a demo reel. one thing i would definitely do is actually go there if you can. don't mail in a resume. walk in their front door and hand it to whomever is there, take a business card, maybe ask to speak to the person in charge of hiring. doing things in person, even if they don't even consider you, is still a million times more rewarding than simply dropping an envelope in the mail. take sample sheets - 1 or 2 pages of pictures of things you've modelled or scenes from your animations. they may be too busy to look at a demo reel, especially if they aren't hiring, but it only takes a split second to look at the pictures as they're sitting your resume in the "file for later" box. it may catch their eye. be super nice to everyone, and try not to be too nervous. (i know, that can be hard!)
once, a LONG time ago (7-8 years) i was doing creature/make-up work, but really wanted to do digital. i had an interview at a place called Threshold, and while i was there, the hiring person introduced me to someone who was walking the opposite way down a hall. the person then pointed at me and said "are you good at masking in photoshop?". i was nervous as hell, and stammered, "ah, no, i don't know..." they needed someone right then and there to do some simple masking stuff. i was perfectly capable of it, but it totally caught me off-guard and i choked. i didn't get that job and it took me years to get into digital work. i always think if i had just kept my cool and said "sure", i would've got started years earlier.
ugh, i'm writing alot, i don't know if this is helpful. i tend to babble.
if you're starting a course in January, maybe just ask for an internship, or some kind of trial period? just definitely take as much of your finished work as you can. that's what you're going to have to rely on for now, that and a great attitude. friendly, willing to take on whatever they want to throw at you, don't complain about any of the work. holy crap, there are SO MANY PEOPLE that do nothing but complain at the places i work, and it makes me nuts. if its that bad, they should leave! if they don't like roto, McDonald's is always hiring! our jobs are ridiculous when compared to other people jobs - nuclear technicians, sewage treatment plant workers, surgeons, presidents and prime ministers... we make entertainment! so have a great attitude, it makes a huge difference.
oh, and tell them straight up-front that you don't mind working overtime, no matter what. that's all these jobs are, overtime.
ok, i should stop now. there's probably some kind of word-limit-per-post i just hugely violated! and i don't even know if this is good advice, but it's what's worked for me.