I might be able to help you.
You would need to make a copy of the camera tape you have onto a VHS tape. Here is what you would do...
Plug an RCA cable from your "video ouput" on your camcorder to the "video input" of your VCR. Then from the stereol, plug an RCA cable from your "audio output" to your "audio input" of your VCR. Then tune your VCR on input and press record when simultaneously playing your camcorder tape and whatever music tape.
This will probably work if you indeed have an "audio output" on your stereo. Altough, if you record with music from your computer, then you have no problem, since you're "audio output" would surely be where you plug your speakers on your computer
Hope that helped...