do not waster money on MBA. the only thing you are lack of is local working experience. It may be a bit struggling to get a decent job at early stage, but if you stick to it, you will get your dream job sooner or later.
it does not matter how high the position you were previously in home country. Most of new arrivals are not lucky enough to get a similar role in short period time after landing (say 2-3 months) most likely have to start from less senior if not junior level and move way up unless you have chance to do internal transfer. Qualification is not that important for your job seeking in Australia.
It is very important to have a good networking everywhere. However, I am wondering whether it is 2 expensive to go to MBA for building a network or finding some connects. People here mostly go for MBA when they areadly have a good job and want a career promotion. And most of them go to MBA for part time or online education.