You are obtaining *surround* speakers, not stereo speakers. For this purpose you need an AV receiver that is capable of producing 5.1 surround sound. That Yamaha is only a stereo (2 channel) receiver, not 5.1.
If you look around @ woot.com (owned by Amazon), they should have some deals on AV surround receivers if you search the home theater sub-forum. I've seen some nice ones of late for ~$199
I have a 50 Watt Yamaha RX-396 audio receiver and am considering purchasing the Monoprice 10565 5.1 surround sound speaker system. The speakers can handle up to 100 W of power and have an impedance of 8 ohms. The specifications say the recommended amplified power is 20 - 100 W. Is my receiver powerful enough to power these speakers? Will it sound okay? Any advice and expertise is welcome! Thank you.