help Tilly the border collie be adoptable

Hello; my name is Jeff. I have been fostering dogs and cats for some years first for Soul dog rescue, and then for Redfern rescue in Denver,Colorado. 28 months ago I was given a border collie named Tilly who was rescued off the streets of Arkansas, and though she was slated to be euthanized because of her problematic behavior, she instead ended up being sent to Denver, and put in my care. She has come a long way with me being in a loving and secure home, and can be sweet with me, but I am not a trainer, and she is still highly reactive to other people coming near me, and to other dogs when we go for a walk. This has made her unadoptable in the time I have had her, and also made me, to some extent, a prisoner of my house. Some trainers have said I should euthanize her, but I can't give up on her like that. I have found a trainer, Jill, who runs Zen board and train, who is willing to work with her for a 6 week period to get her to an adoptable state, or at least where she can be taken care of sometimes by someone other than me. The cost for the training is $2200, which is very reasonable compared to what others charge for just 5 one hour sessions. The board and train is my last hope for mitigating some of her behaviors that I have not been able to change. Redfern is a great deal in debt and cannot help at this time, so any amount toward the needed sum would be appreciated. thank you