Help with French children's book?

I have to make a story in French. I need help revising the story. It's about a boy named Marc and his dog Max who ran away so the kid is sad. Please tell me if its correct. This is the third paragraph from the story. Son parents ont dir a Marc que ils etaient alle a acheter un autre chien. Marc a dit que il ne voulu un autre chien, il a voulu Max. (His parents told Marc that they were going to buy another dog. Marc said that he didn't want another dog, he wanted Max.) Un jour, Marc a alle a l'animalerie. Il a vu un chien blanc et il a voulait l'acheter. Mais il a se rappeler de son compagnon Max. Une fille a acheté le chien et elle avait l'air heureux avec il. Marc avait l'air tres deprime et il desire il pourrait être heureux avec Max nouveau. (One day, Max went to the pet store. He saw a white dog and he wanted to buy it. But he remembered about his companion Max. A girl bought the dog and she looked happy with him. Marc looked very depressed and he wished he could be happy with Max again) Le propriétaire de l'animalerie a demandé pourquoi il avait l'air Marc très triste. Marc lui a dit que son chien Max avait couru loin. Le propriétaire de l'animalerie lui a dit qu'il était désolé d'entendre cela. (The owner of the pet store asked why Marc why he looked very sad, Marc said that his dog Max had ran away. The pet store owner told him he was sorry to hear that.) I need help translating this: Max left the store and went home. The next day he woke up and heard barking outside. He opened his window and he saw Max standing outside on his porch. He ran to open the door because he was excited to see Max. When he opened the door, he ran to Max and started playing with him. He told his dad to build Max a fence and a dog house so that he wouldn't run away.He helped his dad build them. Marc wanted to make Max a name plate so he painted his name on a piece of wood. Marc's dad helped him to put it on his new dog house. When they finished, Marc was happy because Max returned and he built him a nice house. Marc started to walk Max every day and play with him.