Normally you would contact your local election board, but at this point there's probably not much you can do before tomorrow. You shouldn't need it though, you can just look up where you need to vote online though the following, and if you are worried just bring ID (though you shouldn't need that either, unless you live in a state that requires it).
You can get a new card by contacting Voter Registration in you state. You should not need one for tomorrow. Most states only require a picture ID issued by the state DMV. I doubt most people know where their voter registrations cards even are....they get issued only when they change your polling place or you move.