Help Momo get back on his 4 little feet

Momo is a 9 months old Persian cat that was saved from Cairo in September 2014 and today suffered a severe accident today, has several broken bones and internal bleeding and is currently under medical observation. I paid 100 euros on the spot for his treatment, but the vet said that whole thing will cost around 350 to 400 euros. I'm a student abroad and I do not have the possibilities to pay for his whole treatment on such short notice and I definitely do not want to let him suffer and die. Any help is greatly appreciated.