Hi there!
I'm living in Antalya, so I don't really know how things are working in Istanbul.
But from my experience here, it will not be easy to find a job.
Getting a working permit is not easy here in Turkey and defenetly not cheap
(especially when you compare it to what you earn). Also you would probably have to hire someone who can help you get your working permit.
The easiest is of course when you find an employer who wants to arrange all of this for you. Well, the chances of that happening are also very small. Because of the costs for the working permit, they will be much more eager to hire a local. Unless of course they need someone with a unique talent (like the languages you speak). Unfortunatly Turks do not only speak Turkish anymore.
I really hate to say it to you like this...
I also came here one and a half year ago thinking it would all go easy for me.
But of course it is not all bad!
I would never want to go back to Belgium!
It is winter and last week I could sit in my garden wearing a T-shirt.
I must say you feel pretty good then when you see on the telly that it's -5 (or something) in Europe

And slowly I'm starting to make friends here.
All I can say is, get information and don't make any hasty dissisions.