Hi, welcome to HK! I live in Island Resort (just a bit further down from where you are) and have a 3yo and a 16-month old (boy and girl, respectively). We can arrange for some playdates if you won't mind coming over. Please PM me if interested.
If you don't mind going to Heng Fa Chuen (a couple of MTR stations away from Sai Wan Ho), there is HKPPA center there that you can join. You can check them out via this link:
http://hkppa.org/heng-fa-chuen/heng-fa-chuen They're not expensive at all; each 2-hour session comes out to around HK$70 and includes arts and crafts, snack time, circle time, free play, etc.