Qos - Quality of service or Bandwidth throttling

[Demonwebb]

OK, I play games online and my daughter likes watching u tube and movies etc
We share an old router and Im playing my game, then i get a load of lag because she is watching a video. Can anyone recommend a wireless router that would stop one application from hogging the bandwidth? OR another solution? (apart from unplugging her from the router

 

[Demonwebb]

Sorry - ADSL - and Im using an old router - D-Link DSL504, and Orange is my ISP. Due to the house layout, the router will be next to my PC- so I will direct connect via Cat5 - her pc is upstairs (with a trailing cable at the mo) so wireless for her would be ideal.