I suggest that US school is the best choice unless you wanna imgrate to Australia or QUT promise to give you scholarship.
I think that you should choose a school with high reputation if you wanna come back.
QUT is at the City and is a small university. It reputation is not as high as that of UQ in the heart of Australians. I was surprised to know the rank of QUT.
I am afriad that MBA of QUT is not really useful. (from my heart). Why not take IELTS now? It is not easy to get 6.5