Help - Internet radio from PC to stereo receiver

I have a Magnum Dynalab MD-102 tuner which I feed from a top quality rooftop antenna. I have enjoyed many hours of FM stereo music with my setup.

Sadly to say, I am moving to Myrtle Beach, SC where there are few good jazz stations. Here is my question: I find that can still get some of my favorite stations on their internet feed in SC with broadband. I have a Dell PC with two stick speakers and a sub. While the sound is listenable, I would like to get the best possible 2 channel reception.

Would it be worth it to purchase a Terratec Aureon 7.1 Firewire (or equivalent) to connect to my high-end stereo gear or would I still be limited by the quality of the internet broadcast signal, making it not worth the expense. I really don't know if that signal can be improved upon or if it is compressed, etc.

Thanks for any suggestions or hints from experienced people.
I am not an expert on PCs, but this issue is very important to me. Thanks again.

Alan