視頻遊戲達人朋友用完了你的上網帶寬

With your current setup or change to another regular router, you have to live with the slow internet connection unless you upgrade your broadband connection with higher bandwidth.

An alternative is to use a router that is QoS capable, which can limit bandwidth use by 視頻遊戲達人朋友. But that's not something can be setup easily.