So thanks to y'all, I have finally gone to Russo's. What a lovely place! I went there in search of quinces, and they had plenty, and not too expensive either ($2/lb). I wish they'd been a little more ripe, but I've never seen really ripe quinces in stores, so... I'll take what I can get. Also picked up some delicious-looking baby squash, some other stuff, and noticed that tehy had fresh fava beans and fresh shell beans, for those interested. Also had pomegranates--I didn't pick any up (the quinces are enough for now) but might on my next trip.
Thanks to everyone who pointed out this place here!