If you wanted to maximise your money now, you would put it in a super fund and then you'd get a co-contribution from the government and high interest. But, then, you couldn't use that money until you retire. You would be profiting in the (very) long run, but it doesn't seem to be worth it to me because one day you'll have a good salary and you won't have to sacrifice one thing for another and the sum of money won't be such a big deal to you.
In other words, I think you have more need for the money now than your $45,000 per annum earing future-self needs (or even what your retired future-self needs). And hey, if you don't end up earning that much, you'd really regret paying off the HECS!