How do I hear music from my speakers, and Skype with my headphones?

Hey everyone,

I have windows 7 64-bit, and am on an Inspiron 546 MT.

I'm trying to figure out how to use my headphones as a default communication device, and my speakers for everything else.

Headphones: Plantronics Gamercom
Speakers: Logitech VIA High Def Audio? (that's what it says on the sound thing in my control panel)

I already have two audio outputs and both of my devices are plugged in. The problem is, I can't hear them at the same time. When I go to "manage audio devices" in Control Panel, it just shows my headphone options. When I unplug my headphones, it shows the speaker options. I can't seem to find a way to split the sound apart or make one a default communication device (doesn't show both at the same time). Is there 3rd party software I should download?

Any advice is greatly appreciated. (I will frequent this site BTW - not just signing up for one question)