Hi there

I was in same situation as you in september i went to meet the inlaws, but really you have nothing to worry about (although its easier saids then done i know) the only thing i would say is taking his mothers hand kissing it and bringing it to your forehead it is a sign of respect in turkey for people older then yourself, and if she does nt want you to do this she will just take your hand down before you take it up.

im sure if you did this they would be very happy
also try the website

http://www.msnusers.com/englishgirlfriendsofturkishmen

There is a lot of girls on here who have experiences also and will be happy to help. they have been a godsend to me!

i hope this helps and good luck

suzie