I would gradually introduce new light until they were all pagan! LOL, just kidding.
I think sanfransiscojim made some great suggestions. I wouldn't keep the organisation running as a religion though, I'd let everyone eventually choose their own faith and beliefs (with counselling and deprogramming), provide somewhere for meetings (once a week at most!), and then the rest would be charitable activities.
Too much work, not enough reward. All you'd get is a bunch of apostates sniping at everything you did, saying it wasn't moving fast enough, and you'd probably get shot by some splinter group led by a fanatic creepwad like e-watchman when you reversed the blood transfusion ban.
Nah. True religion is personal and cannot be organized.