Getting to Expo is easy via train so your accomodation can be anywhere around the island, as long as it's close to an MRT station. However should you need some ideas, we have some suggestions for you:

Official Accomodation

Capri by Fraser Changi City

3 Changi Business Park Central 1

Singapore 486037

Click here for more information

Other Accomodation

Park Avenue Changi (Click Here)

Grand Mercure Singapore Roxy (Click Here)

Changi Cove

Crown Plaza Changi Airport

Village Hotel Changi

Village Hotel Katong