I'm usually as hard on Janikey as the next guy, but in this case, he actually contributed useful information (although with a negative spin).
The admissions vary from school to school. I'll summarize your chances at each one:
1. USyd - Admissions are based on MCAT and interview, as long as your GPA is above 2.7. If you get a 31-32 on the MCAT, you have a decent chance... although I do know one person who got in with a 29 and a great interview.
2. UQ - Admissions are based entirely on MCAT, as long as your GPA is above 2.7. Last year, a couple of people got in with a 28 (I think) because they applied early... but there might be more applicants next year.
3. Wollongong - Admissions are based on a combination of GPA, MCAT, interview, and "portfolio" (in essence, your CV). Also, they expect you to have a dedication to rural health. There are a lot of factors here, but you might be able to get in despite your low MCAT projection if you have a lot of rural experience.
4. Most other schools (Flinders, Monash, Melbourne, etc.) - Admissions are based on a combination of GPA, MCAT, and interview. You can make up for your MCAT with your interview if you're spectacular, but again, you'll be severely crippled. Also, most of these schools accept very few international students (Flinders accepts a decent amount), so their admissions cutoffs are likely to change heavily from year to year depending on the class size.
If you get anything less than a 28 on the MCAT, the Caribbean is probably your only option.
I do have some good news for you - most of the Australian schools will only look at the GPA from your last 3 years. That means that your 2.47 will be disregarded, and you might have a shot at the schools where the GPA is a factor in the admissions process.
Still, if you want to have a reasonable shot at getting into an Aussie school, you should work extra hard on your MCAT prep. A 24 simply won't cut it. Most schools require that you have at least 8 on every section (and "M" on the writing) before they'll even look at your application. I'd be uncomfortable with anything less than a 30, but a 28-29 might get you in somewhere if you apply early enough.