I have a revolutionary idea for a web application and I don't know what I should do with it?

It will do what Google maps did for finding directions, it is one of those slap yourself on the head ideas that you wish you would of came up with first. I am a graphic designer, not a programmer. I think creatively and visually all the time. I have great ideas all the time, but none like this. I don't have the money to pay someone to build it because it would be more than i could afford. I am afraid of talking about it too much, because I'm afraid the second Google catches wind of it they will take it. Can anyone help?