Using 2 network cards

Hello,
On my computer i have 2 network cards:
– 1 card which is connected to the local LAN/Internet (and which has radio streaming blocked)
– 1 mobile internet modem which i want to use to be able to listen radio stations from the web.
On Windows i enabled both devices, but i can use only 1 at a time, depending which one was started first. I need both (one for local network and high internet volume, the other only to listen 1 web radio station). What can i do (in Windows or Linux)? Thank you.