How many of them are there? Perhaps you could talk to any LBSes/helmet manufacturers/sports megastores/anywhere that has helmets and see if they want to donate some to the program? Also, there must be organisations in your area you could apply for a grant from..? I mean, it sounds like a great cause and you don't need anything flash and expensive to keep them safe. Could be a bit of a pain in the bum to organise, but worth it if it works out.
Drink coffee and do stupid things faster with more energy.