Where to find ? (Istanbul)

This may seem strange but there are some things that I absolutely haven't been able to find in Istanbul. Perhaps you may know? Or perhaps you may be searching for something that others may know where you can find it. I'm crossing my fingers.
Ok here goes:

Reese's pieces
Stevia
Yuka
Cottage Cheese
Crystal Light
Clothes dye (like RIT)
Half n Half

I will post more when I think of them :)

Have a good day.