If you're not a programmer then the tasks you describe will not be trivial, even much more difficult with FileMaker in the long run.
Access from browser, log in with Facebook etc...
I think it would be best done with a HTML solution hosted online since you can just "get" the code that will take care of much of this stuff for you.
+1. You may be able to USE FileMaker in ways for data-exchange and/or to even get HTML content for use with a canned Web solution.
I'm wondering if you have an idea of a canned solution in mind? Also, if I was to use a programmer w/access to some canned aspects of my proposal, any ideas/estimates regarding an approx. cost for development?