Home Repair Assistance for Low Income Homeowners?

I need help fixing the floor in my house. It is falling in. I fell through 2 times already and had to put pieces of plywood down to keep from falling though again. My mother lives with me and I am disabled and we both have very low fixed income.

I have had people tell me that we need to get out of it because it has black mold under the floor and it's going to make us really sick, but we don't have any other place to go and don't have the money.

So is there any charity that can help me fix the floor? It is a 2 bedroom and one bathroom house that is 800 to 900 hundred square feet. I live in south Arkansas and yes I have tried to go through the government and they said they can't help. They told me to look for a charity that might help, but I don't know where to look. I'm desperate for help, so can someone please help with suggestions for agencies that might help me?