kami said:
Repeating is an option, but if you can get into university (even a different course or uni) then it would be better to do that than repeat.
Yes if you can get in take it. I know someone who repeated yr 12 and he totally shouldn't have. Once you get into the university system it is far easier to do well and transfer than do a whole YEAR of school again and try to do better than you did before. The school option is a toss-up really, the university version is way better. And if you decide to change courses some of the units you did in the other course might be able to be attributed to your goal course.