English speakers generally pronounce it as three syllables: Aus-tri-a

Definitely three syllables - Aus - tri- (y)a. It should be in the last column - three syllables with the stress on the first syllable. Xxx I can't imagine why you thought it could go in the first column. If you are trying to fit it into pattern Xx, with only two syllables, either you are pronouncing it very strangely or you have misunderstood what a syllable is.

Phil's right: three syllables. Phonetically (for native-sounding pronunciation), I'd break them down like this: au / stri / ya