The Swissotel is located in a mall called City Centre 2 which has a lot of restaurants, movie theatre and shops. Maybe cheaper to hang out there than the hotel. Or split your time between the two. Many cabs dont know swissotel so just say City centre 2 rajarhat. there is another city centre which is 30-45 mins away in salt lake so make sure you specify city centre 2. It should take roughly 10 mins by cab.

At the intl terminal they have opened a new resturant before checkin called PORT could spend your time there too but guess you will be bored as its pretty basic.

Another mall 20-25 mins away is Mani Square.