Help Save Masi's Leg

Masi is a 7 month old german shephard/pitt mix. He has been part of our family since the week before christmas. He is so smart and sweet- everyone that has met him has instantly fallen in love. He is goofy and playful and loves to spend time outside running. A few days ago, he was outside playing in our fenced in back yard when we heard him yelping and crying. We were downstairs and outside within seconds of hearing him. Somehow he had managed to get out of the back yard and when we got outside he was trying to make it from the street to the front door of our house. His back leg was dangling and he was bleeding from several cuts, His stomach and groin area were also bleeding. We took him to the emergency vet where they confirmed what we thought had happened- he had been hit by a car. Whoever hit him didnt even slow down, much less stop. Masi loves going for rides in the car. I can only imagine how he feels being hurt by something he loves to ride in. We were told that his leg was broken badly- both bones were broken at the growth plate. The only options he has for treatment are either surgery- which is $4000 up front (after the $750 we already spent at the emergency vet), or amputation. We applied for care credit to be able to make payments on the surgery, but were both denied. We have been looking for some sort of payment options, but have been denied for everything we have applied for. Masi is in a temporary cast right now. He is miserable and in a lot of pain despite the pain medication he was sent home with. We have to find a way to save his leg so we can have our happy puppy back.