First of all, you've done a good thing in finding this site: information and knowledge are powerful tools to use when discussing your options with a health care professional, and you can gain both of those things from the members here as well as support, understanding and advice. Don't worry about all the technical jargon: a lot of the gobbledegook will become much more familiar to you if, in fact, you do find yourself needing to come here more often and anything you don't understand, just ask.
If you click on the link below, it will take you to a page which gives a fairly clear explanation of CIS, how the results of MRIs and lumbar punctures can predict whether further lesions, (and therefore development of MS), are likely, and the trials that seem to confirm what you said -- that early intervention with DMDs, (disease modifying drugs... researchers just LOVE acronyms), can delay progression. From what you said, your lesions are separated in space and if it can be shown that they occurred at different times, then they may start to think more along the lines of MS, (I AM NOT A DOCTOR, so please don't take that as medical advice, or a diagnosis: it's just an opinion -- I'd hate for you to worry unnecessarily).
I'm afraid I don't know anything about the availability of different treatments in Australia, just that there is some cutting-edge research going on there. If you're offered different drug options, the risks and side-effects should be made clear to you, but try and remember that things like the recent disastrous drug trial may hit the headlines but are few and far between.
I hope that gives you a little bit of information. This must be a very worrying and uncertain time for you, and I really hope you never have to visit this website again
, but if you find that you do, it's a good place to be!