I went to HK in April and booked a hotel for my young family from this website aaaahotels.net The hotel is called Regal Riverside.
It turned out to be a fantastic hotel on the cheap. The room, service were all excellent although they had some renovation on the upper floors this didnt disturb us much. The hotel is situated near a shopping centre with a kids play area and a park across the river with chinese participating in Tai Chi. The hotel is close to HK heritage muesum which is a must see for all the family. The rate you pay for this hotel does not include breakfast so you may want to take it into account.
Good transportation links from here, we tended to take the bus from here to most places. An octupus card is great value as well.
Good Luck!