if they are both working and getting benefits of centrelink i presume... why cant they contribute more than $100 a fortnight? thats ridiculous to expect you to providethe extras... you arent there mother....

I would tell both your sisiter to get a place together and help them get a place, without needing a full bond through the department of housing. they will give them three weeks rent as bond and the extra rent money should they need it. All they have to do is fill out a form and they could look for private rentals, through real estate agents and then apply, and then get the bond and get out of your hair. they can still choose where they live etc. You need to think of your family.....

they wont ever leave otherwise