Don't panic! We have 2 cats (4 years old) that were none too happy to be sharing their home with a boxer. You have to do it GRADUALLY....
Bring the dog in and restrain him. Just sit close to him and hold his leash. The cat will be curious and come over and sniff. Your cat will probably hiss a couple of times too...that's normal.
Make sure you restrain the DOG, not the cat. Let the cat have free reign to run away if it wants to. Do NOT let the dog chase the cat or corner it. You'd be surprised what damage a cat can do when cornered (even if its declawed, like mine are)
They will eventually get used to each other. Until then, keep them separated unless you are able to supervise.
Good luck...and pretty soon they will either lose interest in each other or become best of friends.
