Ah!
In that case, she's free to do any undergraduate course she wants and get into post-grad medicine with whatever grades she averaged in her three years of undergrad. However, I'm not sure how much weighting Lago Linda/US colleges put onto the name and reputation of the university she attends in Australia, I worry because Avondale is not a that's brought up often at all. She should do some research on this matter. Another option would be to go to a university in a big city (city life/she'll have a blast) such as Sydney (obviously the only city in Australia that matters, I hope the other Aussies don't see this...).
Hope that helped again, good luck!