I think after arrival, you may go to the East coast (which is very close to the airport) to have seafood dinner. then go to hotel check in.
day 1, I suggest to spend full day at the SG Zoo, your kids would love it! It takes a full day for all the shows etc. Bring some spare clothes for changing cos I am sure they will sweat a lot. Elephant ride is interesting. Also, I suggest you to book the breakfast buffet ahead (in HK, they will reply you by email). cos you can take photo closely with Orang Utan. I reserved very early and so they get me the table right beside these animals! I suggest you to take a taxi, not expensive and save you time.
after the day at the zoo, you can just dine at China town or somewhere near Orchard Road.
Day 2, city tour to see Merlion, Raffles hotel, Take the origional duck tour, Kaya toast afternoon tea, then walk around Clarke Quay, dinner at Clarke Quay area, nice place with lots of choice. We dined at the Jumbo Rest at Clarke Quay last time, chili crab is nicer than black pepper crab.
you may also go to night market for Durian (i forgot the place, but you can ask the hotel concerige)
Have fun! and bring lots of sunscreen, clothes and mosquito repellent
Dear Fafa2005,
Don't forget to buy Kueh Lapis (thousand layer cake), pineapple tart and kueh from Bengawan Solo Cake Shop where are in both Terminal 1, 2, 3 of SIN airport. Excellent taste. Everytime I go to SIN for business, everytime I buy them for my kids. My wife favourite: Pineapple tart. Try, and you will love it.
Tick: www.bengawansolo.com.sg