Hi Mustafa, the only film that you can shoot in your 350 is made by Fuji, namely the Fuji Instant FP-100b, FP-100c, and FP-3000b.

I looked in many shops in Istanbul when I was there last year and did not find any Fuji Instant. I ended up ordering film from the US, from
http://www.freestylephoto.biz/ Several other American suppliers carry it, including B&H, Adorama, and Amazon.

Fuji has a distributor in Istanbul. You might check with them and see if they do import Fuji instant films, or if they can get them for you. Their website is:
http://www.filmat.com.tr/

Lots more information about the old Polaroid cameras (including the 350) is here:
http://www.rwhirled.com/landlist/landhome.htm

Good luck! Maybe you can turn Istanbul into "Instant"bul


p.s. Turkey is one of my favorite places in the world. My wife have been there twice and have had a wonderful time each time.
I'll try to post a few Fuji Instant shots I took with my 250 when I was there last year.