Cecelia,
You first have to find an agent who is interested in representing you and presenting your story to a publisher. In today's day and age it's not as easy as your grandfather had it. It has to be something the public is actually into right now. Hence: Harry Potter, Twilight, etc...
The best thing for you to do is get a copy of Writer's Market for the current year and look up an agent who represents your genre. Your only other alternative is to self-publish or vanity press. The latter I would stand clear of by the way.
PJ M