nicolaou
A quick google search found this tutorial on how to record audio playing on the PC:
http://manual.audacityteam.org/o/man/tutorial_recording_audio_playing_on_the_computer.html
There might be some website that can do it as well.
EDIT: You actually already have everything you need if you are using windows.
Video tutorial of how to record audio from your PC with the built in audio recorder.
https://www.youtube.com/watch?v=S5nUsSfiRy4
Good luck and thanks for helping out!