I used this
toplinepet.com harness /leash combo when Laci first came home, its great because its not to expensive and it grows when they do!! Its also easy to go on and off... Jenny is quick to ship also!! I suggest you poke around her site, she has some pretty bows and grooming supplies as well!!!
I do not and didnt use a collar when my puppy was little!! It can get caught on things and they can choke
Also I do not recommend taking her to petsmart until her shots are completed.. lots of germs going on in there!!
I also suggest you wait until she is full grown to get the harness leash combo you want.. alot of people like the Buddy belt and custom leash /step in harness by Chattiesmom... ( cindy) who is also on this site!