Help Dixie get surgery so her leg is not amputated

I am the sole parent and Carer of my son who has multiple disabilities and I myself am also suffering from a rotator cuff injury. We lost our beloved Fox Terrier Dog of 12 years before Christmas and my son and I were devastated. A family friend bought Dixie for us just after Christmas, she is now 5 months old and completely adorable. We are hoping to train Dixie as an assistance dog which will not really be possible if she loses a leg. 

A few days ago a friend was carrying Dixie back to the house from a toilet trip to the back yard when she wriggled free and jumped out of his arms landing on a rug in the hallway breaking her leg in two places, she is very very small with very long thin legs. 

We took her to the community vet, hoping that all she would need would be a cast but within hours that turned into her needing Ortho surgery and failing that, amputation of the leg.

Dixie is just a baby, she has her whole life ahead of her and she doesn’t deserve to lose her leg because of my inability to pay for her surgery. I have considered surrendering her so she can get the surgery but she is very bonded to us, especially my son and she has been very  beneficial for him in a way that nothing else has been. I fear surrendering her would just do her more damage.
This is an awful situation to be in and this is the only option I have to raise the funds needed to help her.  Because of the nature of this break they need to do the surgery early next week for it to be successful so time is running out. We need to raise $4,209.80 by Mid morning Monday 22ndFebruary 2020. Am happy to provide quote from vet.  Thank you for taking the time to read our story.