Help needed for mama beans surgery

Hey there my name is Carolyn and I take care of quite a few Strays in my area feeding them nightly and getting them emergency care when needed but at this moment I am overwhelmed as one of the Strays that I had fed almost nightly was apparently a mama who was injured and she brought her kittens into my garage. She was hopping on three legs and I could smell infection. All of the rescues in the area are full and I was directed to email focus on ferals to be put on a waiting list but Mama beans couldn't wait so we brought her to the vets they clipped her nails down to get them out of her pads and gave her a shot of an antibiotic and pain meds as well as a spray to put on her wounds as her paw was split from the infection draining we brought her home and 3 weeks later when we went to go check on her and the kittens her eyes were gunked and she had a raspiness in her breathing so we brought her back to the vet they said the infection was so systemic that she was unable to kick it and that because of her weakened immune system she now had an upper respiratory infection as well they gave her another shot of antibiotics and took an x-ray and that's when they found the deformities in the development of her extra toes. They said the reason why she isn't getting better is because she needs a surgery to remove those toes in order to be able to get rid of the infection. With having to care for six extra cats on top of my six cats that I have in my house and still maintain feeding the Strays outside I am unable to afford the entire surgery. She's suffering and I feel terrible. I can definitely afford quite a bit of the surgery but can't afford all of it and she needs it as soon as possible before any permanent damage to her kidneys or other organs sets in. Because we have invested so much money into her we do plan on trying to integrate her into our home after we find homes for her kittens she is a stray that went from not letting me anywhere near her to cuddling up next to me on the couch and showing all the appreciation in the world for what we do for her. She has had a really rough life I cannot imagine what it was like trying to protect her kittens on three legs let alone keeping them contained and not wandering off. We believe she surrendered herself to us and brought her kittens to the garage because she just couldn't do it anymore. Any help is greatly appreciated and will go directly towards the surgery for her. Prayers are also greatly appreciated!