Yes, I know and I am sure you do. I would just plan for your uncle to get him now and then have the driver come and get him from your uncles. This is just way too fishy and God Bless you, but you are way too trusting. This kind of thing happens all the time in dogs, and I promise you, this woman is trying to steal your dog.
Be equally as assertive and just tell her WHEN your uncle will be there. Period. I am guessing she will not even hand him over to your uncle, but you can try. She will make up something like since he is not the co-owner, she can't give Austin to him... I guarantee. But try it at least. You have got to be aggressive, or the dog will not get to you. Why wasn't the size thing brought up weeks ago? Do you see where I am going? There is NO CRATE that costs $700.00. Well, there are, but not that you need for shipping. Newfs and Great Danes are shipped for showing all the time.
The other thing you could do is, you could fly there and buy Austing a ticket to sit next to you on the plane. Right now you have to decide if you really want YOUR dog back or you just want any dog. Get a puppy if you want. It's time to make that choice. This will go on forever. She was offering you a puppy weeks ago, so you KNOW she wants to keep Austin. Either go and get him or forget him. I'm sorry, I know you are so sad.