We had our cats at PET HOTEL (
http://www.pethotel.com.sg/main.htm ) in Pasir Ris for one month during the summer, and we saw that they have dog facilities as well. You need to ask about the dog facilities, because I am not sure if they have only outdoor or also air conditioned rooms. The place was clean and the staff were friendly.
Avoid PET MOVERS like the plague - the conditions are disgusting there and the attitude of the staff was totally indifferent to owners and pets. As well, the place is a puppy mill. They breed and sell dogs of so many breeds - so many animals available and all didn't look healthy. I have no idea why the government allows that place to operate.