reinstalled multibit wallet
According to MultiBit's Getting Started, the wallet file of MultiBit seems to be named multibit.wallet, not wallet.dat. You might want to try searching for that instead.

Sorry to break the bad news, but the addresses aren't sufficient to regain control of the bitcoins. If that were the case, anyone that knew your address could grab your coins, and addresses are public information which would make for a very insecure system.

Therefore, you need your private keys in order to transfer your bitcoins.