dd-wrt custom firmware is supported by your router and it's free. I've used it on several months now on my route to limit activity and give your device priority when it comes to bandwidth priority.
My wife in our home is always on youtube and we don't have cable so netflix and hulu takes it's place for our tv watching needs. When on one of these services i used to lag horribly since our internet speeds are not the greatest. It's possible to watch anything at 1080p quality but that pushes our bandwidth to it's limits. by limiting the devices on our network now the quality is around 720p. .... she can't tell the difference or doesn't care and im able to maintain a very playable ping now. Stays around 30 to 40 instead of the 190 area i was hitting before when she was using something.