Welcome and please show pictures of your pups and new puppy when you can. We love puppy pictures.
Just from experience until your female gets use to the new puppy, you need to keep her seperated unless you are present. When home and outside try to play with them together so they can get to know each other better. They will start fighting and your puppy cannot defend itself against an older pup right now. I went thru the same thing with Kodak, he is 3 and my pup is now 7 months old. They get along so much better now but he can still be territorial. He also has just start letting her play with his toys without growling or snapping at her. You really will need to show your older female that you are the boss (alpha) of everyone and let her know you are not happy when she growls. Good luck.