No family wants a cat and dog that fight like, well, cats and dogs. It's not uncommon for dogs and cats to become friends if proper introductions are made. Here are a few tips:
Confine the cat during the early stages of introduction. She'll be more comfortable and less stressed when confined to a bedroom or bathroom where a slow introduction can be made. Allow the dog to go to the door often. This will allow the cat to feel safe while learning the smells and sounds of a dog. Be sure your kitty has everything in the room to be comfortable, and make sure you give her plenty of visits and cuddles.
Use a baby gate to allow the cat and dog to see each other. You might even feed them on opposite sides of the gate or give treats to encourage positive interaction. Increase the length of time spent together gradually.
Once they seem more comfortable with (or uninterested in) one another, you can allow them together, but keep your dog on a leash until they're totally comfortable.