Question for Vets/vet techs

Species: cat

Age: approximately 1 month (her teeth just started to come in)

Sex/Neuter status: female/not neutered

Breed: manx cat

Body weight: 3.1 pounds

Clinical signs: A little cat (who I named Tigger) came up to our porch 5 days ago. She collapsed next to me and I could see something was wrong with her leg. The back right leg wouldn't bend like it was supposed to. She could walk for a bit on it (applying pressure to the very ends of her toes) but she was limping badly and would collapse after a few steps. I think she got hit by a car or soemthing. I initially thought it was dislocated so I took her to the vet the next morning. It turns out her femur is in 3 pieces. There is a shard of bone in the middle that is quite long and sharp. After looking at the x-rays, the vet I went to said that the shard could end up puncturing something if she's not careful. He gave me two options: amputate her leg or get her leg surgery. I just want to know if there are any other options I can take to help her heal. Both of these options are pricey but I just want to help her. Any second opinions about her leg would be greatly appreciated. I will link the pictures of her and her x-rays below.

Duration: 6 days since we found her

Your general location: South Texas

https://drive.google.com/open?id=1Y97g001aZIt-275vf4b96uBDiIXqz641

Thank you, - EM