A notice of non-renewal for homeowners insurance after 20+ years. What are my rights, if any? 30 day warning?

I had a claim last August 2010 due to a leak caused by a branch hitting the roof. Apparently the adjuster noticed then that the roof was not proper since it had asphalt shingles over wood shingles because that's the only time anyone has examined the roof. The roof was installed as part of the purchase agreement and it was my understanding the roof had been totally replaced. It was not and I now know that to be the fact. Last Friday, 30 days ahead of the end of my homeowners insurance policy year, I got a notice of non-renewal because the roof was not correct and because the trees need to be trimmed. I don't understand why they didn't mention to me that the roof needed attention as soon as they knew, for one thing. Now, since they have sent this notice of non-renewal, I am unable to know if they will continue my coverage if and when the new roof is put on and the trees are trimmed. My agent won't tell me. I have not missed any payments of premiums for over 20 years. I'm just really do not know what to do now. I would really appreciate knowing from someone who really knows what's going on and I'd appreciate knowing some options. Can anyone help me with this?