What is the social scene in Istanbul to rub elbows with rich and famous?

[April]

OK...Here is just one way to meet all these people.
Go to Reina. It is a night club in Arnavutkoy. You could go there alone. People fit in your description will be there having a drink.
Make sure you take pride into your looks.
Most girls go there either top or leg decollete. If you go there alone or with another girl friend it will be easier for you to meet other people. Don't go with a guy they will presume that you have a bf or husband and will prevent you to reach your goal to go there. Friday and Saturday nights are the busiest.
Traffic is very bad in this area so don't drive parking is almost impossible. I'd say take cab but you can make it there on foot a lot quicker.
The other location is Bebek comes right after Arnavutkoy. You can see many celebrities around there if you pop into a night club or restaurant even in the waffle shops. Keep in mind it is the most expensive area in Istanbul.
If you spend some time in between Ortakoy where most of the night clubs are, and Bebek I am sure you get to meet with the crowd.

Yes, English is widely spoken in Istanbul especially in the areas I mentioned above.
Best of luck.