This isn't exactly in Sutter Creek but rather in Plymouth which isn't that far away. Taste restaurant in Plymouth is open for dinner only and is very good. As far as picnic supplies, we always stop at Amador Vintage Market which is also in Plymouth (coincidentally, right across the street from one another). I've only been to one restaurant in Sutter Creek and that is Theresa's. It is good, homey Italian food.
I forgot to mention my favorite stop when heading up to go wine tasting in Amador-Andraes Bakery in Amador City. They have picnic supplies a'plenty: cheeses, bread, meats, cookies, etc. Their scones are awesome as are their breads: blue cheese walnut and parmesan are my favorites. Enjoy!