Arhh damn. When I was posting a long reply here, the BOS timed out...damn >_>
Anyhow, as with any science degree (exception of Medicine), the bad news is that you will unfortunately need to revist most HSC courses. But the GOOD news is that, after you've finished your first year of uni, you will never ever see it again.
Here's a hypothetical first year for any science degree
Semester 1:
MATH1031 - An easy math course incorporating some HSC 2 unit maths, and easy 4unit maths.
CHEM1011 - Fundamentals of Chemistry 1A - Incorporating some HSC chemistry, but most of it is new material. The hardest section is organic chemistry.
BIOS1201 - Incorporates some hsc biology, but most will be new material and into a greater depth.
1 elective (ranging from schools of history, philosophy, computing, BABS (biology), maths, chemistry, and physics)
Semester 2
CHEM1021 - Fund of Chem 1B New material
BIOS1101 - Evolutionary Biology - New material, but some say that its the same as hsc biology.
MATH1041 - Statistics for maths, includes probability, binomial theorems, etc. (This Math course isn't required for all majors in science, chances are you only need to do MATH1031).
1 elective
Hope this clarifies things alittle.
In general, if you pass your courses for HSC in chem, math, physics, you can most likely get through your first year of uni relatively easy. You don't really need to take biology for your HSC time though, since in Uni, you'll cover it all over again. In fact Biology is the only course that practically repeats HSC biology, but adds in more complex terms, etc.
If you did do biology in 2006, its ok you can either get an exemption from doing BIOS1101 for your 2nd semester, or just take it, and earn easy marks.