Originally Posted by dutchgirlDH

Uhm - no. Sabiha Gokcen is still where it was, on the Asian side of Istanbul.
It's Ataturk airport that is now closed - services have been moved to the new Istanbul Airport.

Make sure you plan at least an hour between the city and the airport for transfer. You can take a Havaist bus to Taksim, from there walk down the Istiklal Caddesi and there are plenty of restaurants and shops there.