Welcome and best of luck to start!
I would get on to the school's PT association. Most have a "welcome" committee that will pair you up with a established family thats similar. If the school does not ,than be bold and ask if they would pass your email on to any parents they think is a good match. There are a ton of great families in Singapore willing to show you the ropes. There are the country specific "CLUBS" that you can join as well as soccer and rugby youth clubs. The East Coast has biking for hire , and a skate board park to wear the boys out and it's relatively less expensive than say Sentosa. If your adventurous than ferry across to Indonesia to one of the Activity based resorts. A lot of the
International Schools actually send students there for overnight camps. Come June the American Club has apx 11 weeks of scheduled camps. ranging from 1/2 day to full day and different age groups. Theres the British Club you should call and join, they will certainly hook you up with introductions
There is tons to do here and you can do it on a budget or break the bank… it's up to you.