Try to line up the home phone numbers/addresses of any co-workers who have witnessed the harassment.  If you can wear a wire, and record statements, etc, that would be good.  Gather evidence.  Talk to an attorney.  And I hate to say this, but don't quit.  Hang on, and let them fire you, it will be all the more incriminating for them.  Of course if all this wears on your health too much or something, then yes, just look for another job, but that doesn't mean you don't have a case.  You are in our prayers too!