Family member staying with me.

I have a family member staying with me, she moved into my house with me and my two daughters. She isn't working but she does get government payments. I still continue paying for everything like I did before, when she gets paid fortnightly she gives me $150, which doesn't even cover a week's rent but on top of that she will give me a list of things to buy or essentials we ran out of or food she'd like to eat, and keeps the rest of her payment for herself. Ive found that I'm always short because I'm still providing things she could be providing on-top of the $150 given but she doesn't understand that. How do we get past this, or am I wrong for having her pay $150 a fortnight and still wanting her to buy things needed? Would love some advice please.