I suggest you join an NGO to gain experience of setting up and working for a charity. The NGO will also help with your work visa.
I have a school here for 4 years now and it runs and almost pays for itself. My wife and I receive no salary or any of form of income from the school. In fact we take from our other income to help the school stay afloat.
We are volunteers with in our own organization of 130 students and 6 teachers. Helping others get a education that they might not have otherwise has its own rewards,
Though monies would help to expand services for the school such as a food & health programs but getting donations is difficult for small NGOs.  Â
I wish you success in your endeavors, as Madagascar has many areas for growth. However you will need patience and work within the timeline of the country which is slow and has its own customs and culture and beliefs that are embedded in their society for generations. Raising the standard of living in Madagascar will take finding the common ground by looking at the big picture shared by global cultures, and in this case , having a clear understanding of our individual cultures as well.