Hi David, I'm not sure if this will help, but it may be an idea to look on Craigslist and see if there is anyone with a flatbed vehicle truck, nearby who could transport your A8 to a local Audi specialist. If you have no luck there, I did a quick search to see if there was any Euro specialist independent garages nearby. I took a screenshot with some phone numbers
here. It might be worth while giving a couple of them a call and seeing if they can help, or even shed some light on the matter. They may also have a recovery truck.
Keep us posted as to how everything turns out.