You'll have to improve the MCAT score. Without an "O" on the writing section and an "8" on each individual section, most schools won't even look at your application. U.Queensland seems to have the most lax admissions for internationals, and they've rejected people with a 28-29.
The GPA should be fine if you want to go to UQ or USyd (they don't care about your GPA as long as it's above 2.7), but the other schools will weigh both GPA and MCAT equally. You can get in with a 3.0, but only if you score in the 30's on the MCAT. I graduated with a 2.9, and I've been told that I'd be a borderline applicant to most schools despite my 35 on the MCAT.
Australian schools aren't really there to accept the people who didn't get into American schools. If that's what you're looking for, you want to go to the Caribbean. The only reason for an American school reject (like myself) to go to Australia is in the event of a low GPA and high MCAT, since Australian schools place more emphasis on test scores.