How often do municipal prosecutors and judges seek to raise a charge that has been filed against you?

This is very rare but not unheard of.. You need to contact a NJ criminal defense attorney espcially one local to your area.
If you access my avvo profile you will see several legal guides which may help you with this problem.
I recommend the legal guide(s) on what islegal, what is not,hiring a lawyer and the court system.

LEGAL DISCLAIMER…………………………………………..………………………………………………………………..
Mr. Sarno is licensed to practice law in NJ and NY. His response here is not legal advice and does not create an attorney/ client relationship. The response is in the form of legal education and is intended to provide general information about the matter in question. Many times the questioner may leave out details which would make the reply unsuitable. Mr. Sarno strongly advises the questioner to confer with an attorney in their own state to acquire more information about this issue.

It is much more likely for a charge to be downgraded then to be upgraded. On the other hand, if the offense is mischarged as an ordinance, when it should be charged as something under the state criminal code, then the Court or the prosecutor could re-charge under the proper citation. Good luck.

DISCLAIMER
While I do practice law in NJ, this answer is provided solely for informational purposes, for you to use as a starting point when speaking directly with a lawyer. This response is not intended to be, and does not constitute, legal advice; does not create an attorney-client relationship; and, is not intended as an attorney advertisement. I urge you to immediately contact an experienced criminal defense lawyer of your choice, who is admitted to practice law in NJ before you make any decisions about this case.