What I would do is go to the same office that you had the invertiew at.  If you remember the agent's name, try to get to see him or her.  Bring all of your paperwork again.  At the Denver office there is one door your can wait at and the agents come to call the people to their interviews.  You can ask any agent that comes to the door that you need to talk to this agent.  If you do not remember the agent's name then just tell whichever agent you can speak to about your problem.  They may be able to use their A#'s to find which agent is handling them.  

When my wife and I were waiting for her interview, there was a guy there with a similiar problem.  After his interview he had not heard anything for several months.  There was an agent who listened and was trying to help him.  At least in the Denver office, some of these agents seem sympathetic and will see what they can do to help for cases like yours where you are left in limbo.  Maybe in Boston also.

Good luck.