Rescued cat needs leg amputation :(

I found a stray kitten this morning struggling and discovered it had a completely twisted/broken leg. I'm not one to usually worry or involve myself in these situations as I know they can be financially draining. With that said, upon discovering this little fellas bones literally broken and sticking out I just knew I couldn't live with myself if I were to leave him to suffer. After our visit to the animal hospital we have been handed the estimate to get this baby taken care of. He does need to have his leg amputated.. It will cost roughly $2,000 give or take depending on any other findings of medications or sedation needed during surgery. I have been given resources for help, but I would have to surrender the cat. I want to avoid that now that I'm $500 in already & emotionally invested in this little baby. Any help toward this surgery would be greatly appreciated, I would love to be able to give him his fur-ever home with us after he is fixed and healed! Thank you in advance for any help towards fixing our rescue!!