Cortez- small plates/tapas on Taylor & Jones Sts.
Hyde Street Bistro-French - you can catch a cable car on California Street take up to Hyde. This is the Russian Hill neighborhood- at 1521 Hyde St.
cross street Jackson.. Nice ,cozy neighborhood spot- bouillabaisse,hanger steak, classic bistro style, not interesting and fun but good food Fun wine bar arcoss the street.
Too bad Bar Crudo is closed on Sundays, my favorite in terms of fresh intersting plates.
1896 Hyde Street- Cal/Med style food cute place, same street as Hyde Bistro few blocks up.
NOPA if you go around 5-6PM you can get a spot, short cab ride
560 Divisadero @ Hayes
One other suggestion though I have not been but on my list, walk over or take a cab to Nua- however there is the North Beach festival today so it might be a mob scence.
There are more interesting places but I did a quick search on opentable and most of these have openings.