Is there any way I can find out what the insurance policy # for the previous home owner?

Okay so I bought a house in January 2011 and within the 1st week I found out that the heater is not working well. So I had about 3 companies come out and tell me I need a new unit. I live in Phoenix AZ and we had a really bad hail storm in October 2010. So these companies are telling me I have lots of hail damage. My inspector failed to tell me this. My home warranty will not cover it because it is preexisting. My insurance won't cover it because I wasn't covered at the time of the storm. My home owners insurance company says we can go back to the sellers insurance company at the time of the storm but all they need is a policy #. So my question is: Is there any way I can obtain their policy #?