The store I use in Izmir is a subsidiary of an Istanbul shop, and they carry film but not a great choice.
It would be better to say what films in particular, for instance I can order Delta 100/400 and I'd get FP4/HP5 as that's what's they import. There are plenty of camera shops in Istanbul, but most are totally Digital, however a few have a reasonable range of analog materials. If ooze doesn't reply to this thread PM him as he lives in Istanbul and can point you in the right direction. My 4/5 visits to Istanbul have always been too short with no time to visit camear stores or catch up with Turkish APUG members there.