I think I need a signal booster. Any recommendations?

I have a smart TV in my basement but the airport and mac are upstairs. When I wish to watch a movie online on the smart TV, it will frequently stop and give me an error message. Sometimes it will say I don't have enough bandwidth. Sometimes it will give me other error messages. I've been told that I need a signal booster to boost the signal down to the basement. Would that help and if so, what kind do I get?

Thanks.