Mate, it is more a family law question.
So, methinks - assuming you do not damage any property and assuming there isn't an AVO restraining you from entering the property, then just go get your stuff. If she throws your stuff away, there ain't much you can do. You could seek re-dress through the courts but it will cost so much, you might as well go buy new stuff.
Go to the local cop shop, let them know that you intend to go to the house with a van or whatever and go get your stuff. Take a witness, wear a go-pro camera or do an audio recording on your phone. While it is technically illegal to record someone without their consent, the cops might still be prepared to hear or watch any recordings to ascertain what was going on....
If she has changed the locks - then forget it. If you break the locks you can get done for damage of property. In short - you're screwed...
So if you go to the house do nothing illegal. Do not touch her. You're better off going to the house when she isn't there. If possible.
Now as far as the mortgage goes - were you paying some / all or none of it before separation? Are you paying any of it now?
Last question. Do yo have kids together?