Sorry for the late reply. If that is your main goal, I suggest doing a combine degree at USYD because its internationally well-known. You may also aim to do honours and PhD if you're good enough and are interested.
There's really no point in doing a B.Ed/B.Sc and THEN do a masters in teaching because its basically the same unit but compressed into 2 years (in fact i dont even think you're allowed to do a masters if you have completed the combined degree). What's the purpose of wanting to become a teacher? Do you want to teach in Australia for the large part of your career or do you want to teach overseas?