Yeah I know a guy trying to do that this year. Just pick subjects like STAT170, ECON110, ACST101 that you would do in a comm degree and study your arse off. I'd say min of credit in everything (GPA of 3) might be sufficient, but it could be higher
At Macquarie, with the exception of transferring into combined law, the method of transferring is outlined here, which you would have found if you googled it.