Need Help Making Katara's (avatar the last airbender) Parka

[Cosplay Freak]

Halloween is almost here and I need help. Does anyone know how to make Katara's parka and/or dress? I need help the most with her parka. Do you use a pattern? Or do you just make it from scratch? Or maybe you have some other techniec? If so please tell me. I have little time and need help. How am I going to make it. Are there any colors you suggest. Anything at all will help. Thank you!