It sounds like you have made up your mind to go. A local restate agent should be able to help you find a rental that you can afford. You may be entitled to some help from Centrelink, but that is a something that others on this forum may know more about than me.
As I said previously, if you do move into a rental, the matrimonial home becomes your husbands responsibility. He will have to pay the mortgage and utilities since he will be living in the house. You will not lose any legal entitlement to the house by moving out; if that is what you want to do.
When you can, please get some legal advise; preferably before you move. Apart from the financial matters, there are parenting and child support issues that also need to be sorted. The WLS and RA are far more qualified to guide you than I am - especially since children are involved.
If you want to talk, let us know how you are going.