Abuse and violence should be reported first to the police, if not only so there is record of it.
Since the child is not yet born, this matter is not a parenting matter, but a domestic violence matter. What you can do is apply for a domestic violence order against the mother. The police may do this on your behalf if they feel the circumstances are serious enough, however you can also apply for one of your own accord if you so choose.
For more information about domestic violence orders in Queensland, see here:
Domestic and family violence - Queensland Courts
For information on how to apply for an order, see here:
How to apply for a domestic violence order