Is there a way or possibility?

looking for ways that if I click a button it will post a wall to their facebook wall status and create a status on twitter?

I know that we have to be friends but to just even send a message of invite to their fb email if they are not friends.

Something that will notify them and have the possibility of their friends seeing that he purchased a product, invite other friends or whatever.

Please advise

Both FB and Twitter have developer APIs. They are web-oriented of course, but you should be able to "talk" to them using a FileMaker plugin that handles POST requests such as ScriptMaster, Fusion, Troi URL, etc. Good luck.