copyright

[Geaaronson]

Okay, you probably will be thinking by the end of this posting that the guy is nothing more than a wannabe who has not been around the block, wants to get rich quick, etc. etc. but here`s the situation.
I have been teaching ESL for five years now here in Mexico. I have an idea for a learning program I have never seen in any bookstore. It is directed for the intermediate to advanced student. No, I am not going to tell you anymore than that. Should I do so, I would jeopardize a copyright to the concept.
I have visited New Options Bookstore, Gandhi Books, Londres Bookstore in Merida, the American Bookstore, and dozens more that deal specifically with texts for the non native English speaker. Never have I seen my idea on the shelf.
The question is, without having the means to copywright the idea which would involve the expenditure of 10`s of thousands of dollars to create, how would I go about doing so without jeopardizing my future copywright.
If I pitch this idea to Oxford, Longman, Cambridge, etc. etc. what is there to protect me from their stealing the idea without financial renumeration?