There probably aren't any since all the hotels there are AI and not many people will drive that far from town for dinner. My suggestion is look into restaurants in town and plan on coming in at least once. Sunday is a good day since there are minimal/no cruise ships.

You can rent a car, tour the east side then finish with dinner in town

Forgive CP for not realizing that there is a very well respected (but small) restaurant right next to the Iberostar called Alberto's. CP stays on the north end usually but I have stayed at the Iberostar twice. I don't remember any others within a reasonable walking distance, but there are a few others spread out along that zone. On the other hand there are way more than you will have time to patronize in town that are very good too. If you ask at the front desk they may be able to advise you of any others that may have opened since my last visit.

I heard albertos is just to your right when you walk on the beach. We are staying at the iberostar on jan 7th and plan on checking it out for fun. This is a good websight

www.thisiscozumel.com