Switch from Tier 2 general dependent to something else?

Hello,
My husband is on Tier 2 general visa and I am a dependent. We're both employed and have about 1.5 years left before we will be eligible for ILR. It turns out my husband might be losing his job which means our visas will be cancelled shortly after. I have 2 primary questions which I'm hoping someone can help answer.

1. How much time do we have after my husband loses his job and before we're asked to leave the country? Does that start from the last day of employement, including notice period?

2. In the meantime, anything I can do to upgrade my visa to another visa category perhaps so my husband can be dependent and has enough time to look for a new job? Something to buy us time and yet not jeopardise our chance for ILR in about 1.5 years?

Thanks
Anu