I'm doing this course at the moment that is basically just night school. I'm doing Certificate II in the Music Industry, but at the same time they run regular high school subjects simultaneously. The best thing about it is that it's all government funded. You do 3 hours a week per subject (all in one go) and the basic fee for the subject is something like $18 for the YEAR. It's 3 hours a week, normal school term regulations apply, getting back into the habit of things, it counts towards a HSC certificate (though you could probably just use it for the purpose of getting back in the habit), and it's only $18. My friend is doing a Chemistry and Maths B subject so that she can go to uni next year. You should look into something like that.