Hello,
I have a dog and a cat and when my partner and I go away we use a number of options.
Firstly, on Truong Dinh Street there is a "khach san cho meo", dog and cat hotel, where they will board your animals (outdoors in cages) for not too much money.
However, they also keep baby bears there and I think that really freaked out my animals! I used them once and never went back.
Another option is that most international standard vets (Pet Health on Au Co for example) also board animals. It does not cost too much (maybe 60,000/day for a cat and dog). My animals also hate this place, but we use them when we have to.
The BEST option is to find a local woman you trust and who loves animals and pay for them to come to your home to look after your pets. This is much less traumatic for all involved and can be arranged fairly cheaply!
I have a woman friend who I trust to do this, and she is currently looking for extra work. If you want her contact send me a note and I can arrange a meeting!