software that routs signals controls a router unit which costs several hundred dollars.
Headphone jack to amp to speakers is the inexpensive solution.
Any small integrated amp or tuner amp, or power amp will work for that application.http://www.amazon.com
/AudioSource-100-Watt-Monoblock -Power-Amplifier/dp/B00006I51M $59
check amazon, e bay, crutchfield, or a second hand store.