Coming from a current uni student with experience in all the courses you're thinking of doing..
Cut this BS about working your ass off. You may want a part time job, but don't work too many hours.
You're going to go out and go drinking, you're moving out of home. You're going to socialise and have a good time etc.. you need to think about your course.
Your course to get into uni is harder than first year uni.
There's no way in hell I could ever hold up a part time job more than 5 or 10 hours a week with my course. I choose not to have one so I can get in debt now, get decent marks and make it all back a lot quicker later. My course will be similar to yours in that there's assignments and class you can't miss, or you fail automatically. Extra years spent studying cost a lot.
Teaching does have many hours in work, and not everyone can do it. Most people I know have dropped out of teaching because they'll kick you out if you're not smart or dedicated enough. First year should be fine for having a part time job, but a lot of teaching students I know wouldn't think of having a job in the few year(s). Those that finish it love it, and most can't imagine doing anything else.
Yes you can live off $150 a week, but if you're going to have a life you'll need an overdraft or another source of money (that isn't a credit card). The $150 a week is there for people whos parents support them, the student allowance is for students whos parents don't earn enough to support them.
Oh, and work your ass off when you're not studying. You'll need the cash. Although this makes you a whole lot lazier when it comes to uni work..
Right now I'm working for the uni. I just can't win...