help needed! do i need visa just for one stop in Vancuver

My family lives in San Francisco, CA, US. In July, we will take vacation in China. The flight we are going to take has one stop in Vancouver, so we need to stay in the airport for 5 hours. It is the same thing on our way back to SF (we will stay in Vancouver airport for 8 hours.
My family situation is: two kids are US citizen, my mom and I are China citizen but holding US green card, my husband is China citizen and holding H-1B working visa in US.
My questions:
1. do we need to apply visa to Canada? We won\'t go anywhere but stay in the airport for several hours.
2. If we do need visa, what kind of visa we need to apply? how and how much for the application fee? How long it will take for the whole process?
3. Do we need to go to Los Angeles?

Thanks for the help!