The restaurant on the motu is COCO BEACH (on Motu Tiahura), and its shuttle location to take you over to the motu is near the IC. The boat shuttle is free, and they offer pickup from hotels for around 700 cpf if you don't have a rental car. I know the owner, and have not heard that it is closing. They are open Friday morning to Sunday evening, 11 a.m. to sunset, and you can call them at 72-57-26 for more information and a reservation. The food is FANTASTIC and reasonably priced (in proportion to other nearby restaurants).
The beach restaurant at Les Tips is a good choice too, but only for lunch -- they are not open for dinner. It's a nice, open-air restaurant with a great view, the food is French/Italian, and the prices are mid-ranged.
Of the two, I would choose Coco Beach for a fantastic experience -- you simply cannot beat the view from there, and can use the beach for some great snorkeling the rest of the afternoon.