QoS may not be able to limit torrent since it is designed to get around most restrictions but you can try I guess.
You will need a router that has the ability to hard limit the INBOUND rates of traffic. This is very uncommon. Some of the high end tp-link and asus routers can do this. If you want a cheap router use one that you can load dd-wrt on.
The configuration is sorta backward because it really is a hack and only works on well behaved applications. youtube and netflick it works well on.
Say you have 10m on download bandwidth and you want to ensure your game machine for example gets 5m. There is no way to just say "guarantee 5m to user xxx" You can on outbound but on inbound only the ISP can do that. You can not...