You don't say whether you have private cover @kcteds (or maybe I missed that). I do have cover but was about to cancel it. Financially, things have been very tight but I have mostly gone through the private system. I have discussed the finances with each of my doctors and in each case, they either bulk-billed or the gap was very small. The hospital, of course, is another matter - but my private cover was good for that. My surgeon does practice in the public system, too so I would have seen him there if necessary. My rads will be done publicly. My cousin, however, has gone completely public. She was diagnosed a few weeks after me with the same cancer (last Christmas) and I think her first surgery was around May - mine was 2 weeks after diagnosis.
At this stage, I too am uncertain as to whether I will go for a reconstruction. I think that's where the money will come in to it and from reading on this forum, how quickly you can get through in the public system depends on where you live.
So far, the major expense (if you don't count the health fund premiums) for me has been the gap charged at the specialist lymphodema physio for my cording. That is almost $60 per session and, while I hoped that it might be limited to just a few sessions to "fix it", it's looking like it might be a regular long-term thing.