Definitely patience is key. She's new to you and you've never known another GSD. Imagine how it is for her having known other humans. I also recommend the 2 week shut down. It seems like more work than it really is. I did it with Gunther as a brand new puppy and again when he and my other dog had a scrap. Only that time it was the other dog who was on shut down. Both dogs learned their place. Please, keep us updated how she's coming along!
Hail Gunther 7-2-2013
If at first you don't succeed, destroy all evidence that you ever tried.