AT&T 2wire DSL & VOIP

So I have AT&T 2wire DSL. I also have a very basic VOIP that connects through a PC USB Device. I would like to setup a QOS, what would be the easiest way to do this. I assume it is going to be to buy a router that already has QoS and put it behind the 2WIRE router. If someone has a better idea please let me know.

Regards,

J