Legal presence in US after company shutdown

[Meimei]

This is my situation. I am currently in my 6th year of H1B. My company has extended my 7th year H1B in June this year since I have a pending labor cert for more than a year and I have already received the 7th year approval. Recently, my company announced that they will close down our office in Dec. My question : If I am not able to find new employment, can I be converted to H4 after the closure or do I have to leave the country? FYI, my husband is in his 4th year of H1B. Appreciate your advise.