Ena's Surgery

Please help us give Ena a longer happy life, she needs an amputation to her right hind leg. Last night at around 7pm her own biological son (who we adopted as a kitten 5 yrs ago) chased after her and our Golden Retriever (whos never done this before) grabbed on to her and shook her so violently causing her a fracture. We quickly rushed her to the vet and they confirmed that she had an open comminuted fracture of her right tibia, fibula and needed either surgery to try and repair it, amputation or euthanasia. Euthanasia not an option for us as we believe she still has so much to live for and surgery is expensive costing anything from $3,000-$5,000. Unfortunately we have been struggling financially for a while now after we had a kitchen fire two years ago and can't afford the amputation. She need this surgery ASAP since shes not able to move or eat until the surgery. We were given pain medication temporarily to give her every 8 hours but that doesn't take the pain away completely and placed a temporary cast on her (which she removed a few hours later). We are asking for help from anyone who have been in our situation or believe pets/animals should have a second chance at a good life. Ena deserves a good life.  Thank you.
 
A little about Ena:  
She was born about 8 yrs ago to my sisters other cat. Being the only kitten she gave birth to, my sister decided to kept her. She grew up being tormented and bullied by my then brother-in-law and she became an angry and a paranoid cat that didn't trust people touching her.  One night she was put outside of the home because she attacked my sisters hand. She would still feed her and let her into the home when she wanted but mostly stayed outside. Then one day my sister needed to do an emergency move and asked me to get her two dog from her apartment after her ex-husband neglected to take care of them. I asked her " What about Ena?" who had 2 kittens just outside of the apartment aswell. She told us we could leave her and the people in the community would take care of her. Of course I didn't think that was the right thing to do so we brought Ena and her kittens home with us. After two months we were able to adopt out the kittens and spayed Ena, after countless litters. Living with us she has made a complete personality change, she's sweet and let's you pet her so much without scratching you. Her purrs get louder and louder everyday. We've had her now for 2 years and she has been a great addition to our family.