The key is to try to be as gentle as possible without really disturbing her as much as possible.
Get a really BIG container, you might hit a really good sale, because it is the end of season now.
Then, buy Miracle Grow transplanting liquid, they sell it at all the big box stores, by the house plants.
When you go to dig her out, Dig really wide and really deep.
Deep as you can, and transfer as many of her roots as possible into the really big container.
The more dirt you take out with her roots, the better.
Then, transplant her as soon as you can, digging the hole nice and wide and deep, applying the transplant solution according to directions, putting her in, and watering her before filling back up with the dirt you dug up.
Water her again and put more transplant solution on top.
That stuff is great!
Follow the directions and water her every day for about a week, or until you are sure she is well hydrated.
She will be fine.
Remember, the more dirt on her roots, the less damage you will create.
And you will have her at your new home, it will feel like home instantly.
Good Luck to you!