D.B.
I have no idea why someone decided to give you a puppy when you have a newborn. Or was this your idea? And how did you get a puppy at 7 weeks? Usually they aren't taken from their mother until 8 weeks.
Have you ever owned a dog? It doesn't sound like you have any experience. Have you been to a vet yet?
You need to get into a class or have a professional trainer come to the house (probably the latter since your puppy hasn't had all its shots and can't be with other dogs yet). You need to be taught the necessary skills.
Puppies take time, as everyone says below. You have a baby so you know you'll be doing everything for years. You will be doing everything, every hour of the day, for a puppy for a full year, and if you don't do it right, you'll be doing it longer. Everyone, including the dog, will be miserable.
Truthfully, if you don't have time or knowledge, I would quickly re-home this puppy to a knowledgeable dog owner before the animal is attached to you. When your child is older and you have had time to learn about dogs and decide if you are ready for a 15 year commitment, then you can volunteer at a shelter and learn about dog care. You're not ready.