Recording a particular sound from video

Guys i have a video and from which i need a sound as a mp3 file. So suppose the video’s 12 mins 23 secs has the sound , i want to record it from there to 12 mins 26 secs , please tell me what software should i use to do this or any other way.
Answer #1
So you want to record three seconds of the video soundtrack?
this will record any sound coming out of your pc speakers….
http://www.audio-tool.net/audio_recorder_for_free.html