This is what I would do. Pretend for a few minutes that you returned her. She is really gone. You know you will have a new puppy soon. How do you feel? If you think you can do it then return her. If you can't bare the thought of not having her keep her.
I know how you feel about the money. I went to look at yorkie puppies, just wanted to look. They put a puppy in my arms before I thought to ask how much they cost. When they told me he was $1800 I said forget it. I'm not paying that much for a dog. Of course I left with him.
Socalyorkilvr is absolutely right. He was worth every cent and I never regretted taking him.