I am using a device called an 828MK2 from Mark Of The Unicorn, or MOTU. You can find these pretty cheap on Ebay, in the low 100s. It has 8 analog inputs as well as 8 analog outputs, so for example, you can have ports 1-5 streaming to radio reference, port 6 going to a local speaker, port 7 being recorded by a completely different program and port 8 streaming to a friend via a private audio stream.
There is a lot of flexibility with this device and many others like it. They also have digital inputs and outputs for even more capability. Go to sweetwater.com and look in the section called Computer Audio/Audio Interfaces/USB or hit this link:
USB Audio Interfaces | Sweetwater.com
There are over 150 items to chose from here, so it will seem a little crazy at first. Check some of the stuff out, and by all means ask questions here or IM me.....or call Sweetwater. They have some of the best people answering pre-sales questions and they actually use the products they sell!
Audio interfaces keep comign down in price and up in feature/functionality. When you narrow it down, post back and we can try to help you get it all going.
Good luck!
Vince