How do I get my chihuahua to get along with my new puppy?

I have a three year old chihuahua, Suki, in my home and she is very fond of people, but is insecure and grouchy around other dogs. I just got a puppy from the pound, Charlie, who is half bet hound/half labrador retriever. He is 8-9 months old. Suki doesn't like when Charlie is around her most of the time and she growls at him and sometimes curls her mouth and shows her teeth. She does this when he is really energetic and playful, but sometimes she does it when he is completely mellow and is just physically near her. I want the two of them to get along, but I don't know how to get Suki to chill out and accept the dog. What should I do?