It appears that no one else in this forum has much experience with this specific course. Fortunately I am enrolled in it at present and can hopefully shed some light for you.
MonkEE has covered generalised answers so ill get right to the point.
1. Your first question is do you have to study mathematics if you want to become a biology teacher. The answer is yes, there is no way around it. If you are completing a B Science degree in any major (from any of the major Sydney universities I have explored) one unit of mathematics must be completed. One unit means one "class", if you will, over one semester consisting of roughly 12 lectures and tutes (for maths). There are varying levels of maths you can study but even the lowest ventures into minor calculus. It is more than do-able even without prior knowledge with a studious effort.
2. This could get slightly confusing. In your first year you will have to study an accompanying science subject(s) along with your major. For instance: Your studying biology in your first semester you will also have to study a chemistry or physics subject. This would then continue for your second semester. Most biology students opt for chemistry over physics for fear of maths. This is enforced (as MonkEE has mentioned) in accordance with the NSW DET for teaching Biology at HSC level:
"A major in science (3 years of degree level study with at least 4 units at level 2 or above) of 4 units in biology and 2 units in one of chemistry or physics."
Source:
http://www.nswteachers.nsw.edu.au/I...rements for Secondary Teaching - Mar 2009.pdf
In short you will have to complete a minor study in chemistry or physics throughout your course to fulfill this DET requirement.
3. I believe your next question is that will you be able to handle the course work for the subjects you have not completed during your HSC. I find it hard to comment on this has I completed biology, chemistry and physics during my HSC and am doing the corresponding units at university. All I can offer is that if you undertake reasonable study, attend lectures and actively seek help if needed there should be no reason why you cannot pass (or better) these subjects. The pace of the course work is considerably faster than HSC level and some lecturers are better at delivering it than others.
4. There are a large range of biology and chemistry subjects but a much more limited range in physics. UWS Science also has a large geochemistry selection. All subjects can be found on the UWS site or in the course handbook that can be found with a little bit of digging on the site. Once again my advice on prior knowledge is above.
5. Correct. You will study the B Science for 3 years then the M Teaching for 1 to 1.5 years depending on your study option (accelerated or full time). You will study subjects concurrent with your selected major or "key program" as UWS likes to call it.
Hope this helps you make an informed decision.
Good luck.
entirely answered my questions!!