I thought it was fair to ask for half of the extra activities they do. After looking at the csa website I believe as they get older the percentage will increase as children cost more as they get older. Does anyone have an idea how much public schooling will cost me? I believe I will be getting a school card and have been told it shouldnt cost much at all.

If you havent guessed, I am quiet new to all this stuff. Ive never been through anything like this before, never had to go to centrelink etc etc we only just separated in January and Ive always worked until May last year before I had DD2. Stuff knows where Id fit work into my day at the moment, I take my hat off to single parents who work and care for their children full time.
It wont be easy for you, but if you have a good relationship with your ex maybe you should draw up a parenting plan and come to an agreement on how the finances for the kids will be organized. he might agree to pay a little extra.

otherwise your option is to go thru CSA and they will base the amount of maintenance on his income. You should also get the parenting payment if you are a single parent now...that will likely be close to $400 per week with 2 children. You can claim rent assistence too.