My neighbor rescued a female mongrel she calls Bear (because she's brown and has cute round eyes like a teddy bear) from the streets. She was a stray who had been living in the drains near my neighbor's office and was probably abused and abandoned a while ago.
Bear was terrified of people and would only allow my neighbor to pat and hold her. She behaves in a similar manner to your dog Holly. It took her almost a year to get used to having people around her. She gradually grew accustomed to having people around her and will now allow strangers to pat her.
Let Holly take her time. Rewarding her will be a great way to encourage her and to give her confidence.
Good Luck!
