Please help us save our cat

Bonapart , Ontario,

Recently we decided that we wanted to get a dog, so we found one on Kijiji and picked it up. The people we got it off of said it was good around children and small animals so we said ok and we brought him home. He was really nice when he was in the car and was friendly to our kids but when we brought him inside he went to meet one of our cats and the cat swatted at him and he attacked, biting him in the eye and he started shaking him also so we were forced to bring the dog back to the owners. We then took our cat to the emergency vet clinic and he was looked after and it cost us around $300 for bringing him there and for medication, but we now have to bring him to a vet to get him re-assessed and if he has developed or is developing glaucoma he may need to get his eye removed and we don't have the money to get it done because we are in a very tight spot right now and it could cost up to $1000 depending on where we take him so the only other options would be to get him euthanized, which we still don't have the money for that even, and I don't want to do that because he is in good health besides his eye. Or surrender him to the humane society in hope of him finding another home and if he doesn't they will probably euthanize him anyway, and he doesn't deserve that, he is such a sweet timid cat and loving companion to his brother who has never been separated from him since birth and a very dear part of our family. His brother was actually looking for him the day it happened when my girlfriend took him to the emergency clinic and he has been watching over him ever since, and our 2 young children would be devastated if anything happens to him. If there is anyone who has a big heart for animals please help, we don't want to lose him and we don't want our children to be upset and his brother separated from him. Anything will help and we don't have much time. Please, please help. Thank You for your consideration, Chad