I probably would stop trying to go through a rescue. You have an unspayed female, lots of rescues will not place a dog if there is anything not altered in the home. And, it sounds like there is a clique where they have your number. Probably, it is their loss.
You have two dogs now, and one of them is a puppy. Instead of getting another dog, join a training club, try something new, like agility or nosework or flyball.
Don't give them a second thought (the rescue organizations), when your youngster is between 2 and 6 years, buy another GSD from a breeder.
There are many needs that dogs have. One of those needs are homes. But there are many other things that they need as well. Donating food and bleach to the local pound, volunteering to walk their dogs regularly, are a couple of ways that you can really help dogs in need.
Another thing that would really help dogs would be free training classes. I know, people ought to pay to take dogs to training. But once your bitch pup has reached trained excellence, offering a saturday morning obedience class to people who are struggling with their pups, could actually help dogs succeed in their homes. Personally, I think one of the reasons a good percentage of dogs get dumped is because no one has taught them some very basic obedience -- manners 101.
There are more ways to help dogs than rescuing individual dogs. You can transport dogs for people. You can possibly donate money to programs that help struggling dog owners meet veterinary needs for their dogs.
Jenna, RN CGC & Babs, CD RA CGC HIC
Heidi, RA CGC
SG3 Odessa, SchH1, Kkl1, AD
Ninja, RN CGC & Milla, RN CGC
Joy, Star Puppy, RN CGC
Dolly CGC & Bear CGC