Had something similar recently. The insurance company had sent the renewal to our previous address, we'd only just moved house. We'd written to them with the change of address details but they said they never got it. Because we didnt take them up on the renewal notice (that we didnt receive) the insurance lapsed. Sods law obviously kicked in and we had a small accident, went to check the insurance and found out we didnt have any! It had expired a few days earlier. In the end we had to settle the other persons claim for damages ourselves without involving their insurance company. This was for a minor accident - could hardly see the damage, I dont know what would have happened if we had to go through the other party's insurance.
It wasnt a good situation, I know how you feel. Can you settle directly with the other party?