I'd say Rocky and Carlo's, but it's been closed since the fire. If you want another real St. Bernard experience, go to Tony's on Judge Perez for lunch. The Arabi Food Store, on Friscoville, has great muffulettas.
Since you will be in the FQ all the past posts on good eat places fit. Also, there are some good food booths scattered around the stages. Coming from/going to Arabi you will also be passing all the good places in Bywater.
There will be more good choices than you have stomach!!