I have a two years old Golden and Dahschund. The two dogs get along very well despite the difference in their sizes. Back in April, I saw a stray kitten underneath a car. She lookes so fragile, so I took her home an named her Mitchell. At first my two dogs were surprised to see a new creature in the house. The didn't like her at all, they barked non stop. So what I did at the time was to put the dogs in the backyard and the cat inside the house. I happen to have a glass door as an access to the backyard. During the separation they can still see one another through the glass, this way both the cat and the dogs got used to each others' presence. Bit by bit I brought them together (just for 5 minutes at first). Gradually I increase the time of their meetings. Now they are so used to each other, I can't separate them anymore.

I hope the trick work out for you.