Rod,
Just marrying your girlfriend and asking for a work permit in Brazil is not enough. For working in Brazil as a professional pilot you must hold the brazilian nationality. So, after getting married, you will have to live in Brazil for at least a couple of years, and than apply for the brazilian citizenship. In your particular case, I would rather do the other way round. Bring her to Australia. By the way, the aviation jobs in Brazil in the present moment are quite bad, as about 600 of the more experienced brazilian pilots are working abroad.