How long can I extend my Non-B visa, and what should I do if it only extends until March?

Hi all. Grateful this page exists.

I am on a Non-B teaching visa - issued October 17 about 90 days ago. I finally have my work permit and other necessary paperwork from the school to go back to immigration and extend the Non-B.

My question is twofold:

First, will the Non-B be extended for the remainder of the year (until October 16, 2019) or will it only extend to the end of my contract with the school in March?

Second, if extended only until March, what is best course of action to take while I am either waiting for a new contract or looking for a new school?

This is my first time doing this and since it appears the school doesn’t have a clue, I am unclear what to prepare for. Thank you!