Well I feel bad. My mother lives with me and gets room and board in exchange. I can't afford to pay her. There's just not much money left after paying bills. Sometimes there's no money left and I get behind on things.
I figure since your mother lives on her own, you should do as much as you possibly can. But I suggest you just sit down with her and lay it out. See what's left after you support your family and pay the daycare expenses. I've never figured out how people have anything left unless they just don't have cell phones, cable, buy only the cheapest (fattening) foods, live in tiny little houses maybe? :) Hopefully, you are better with money than I am.
My mother is a saint. She is a huge help. I try and give her as many choices as possible like, do you want to cook, or do you want to take the kids outside for a bit? Do you want to stay here or drive someone to school? Do you want to change diapers or sit with a grumpy baby? I think giving her the choices makes up for her not getting much financially out of the business. Thankfully she has her social security for spending money.
Is your house big enough for your parents to move in? :)