Here are a few suggestions:
Flanders Fish Market-East Lyme
Abbott's Lobster in the Rough-Noank
Dock and Dine-Old Saybrook
Bank Street Lobster House
Abbott's and Bank Street were featured on Rachel Ray's $40 a day show-bargains.
Dock and Dine and Go Fish a little more expensive
Flanders very good and reasonable.
Lots of choices...enjoy