I've had anywhere from 12 to 90 babies come out of my female before. I don't take the babies out of the 10 gallon any more, but I still had around 90 to bring to the LFS
this last time. The first time she gave birth I only found a few, but I think she also HAD fewer babies, not just that more have started surviving
If you want to be able to have her babies survive in the future without having to be removed from the tank right away, plants would help, especially floating plants like duckweed, water sprite, or anything that sends leaves to the surface like dwarf lilies, or sometimes banana plants.
The babies should be okay even without live food, just crush up whatever you give the parents into a fine powder. If you don't already some algea tablets or flakes, your mollies will love them.