HDMI is a technology before its time during its time. It's had several modifications, including 1.0, 1.1, 2.1, 3.1 and so forth. While the video quality has always been 1080p, the audio has undergone several changes during the years.
It's possible that the HDMI port on your laptop isn't designed for audio at all. I would recommend looking for an optical, or try jacking your stereo up to the line out. Even if you were somehow successful getting the audio into your tv, HDTV audio is poor at best.
Extend a splitter cable from your headjack to the stereo with the red/white cables. it'll do you well, and most receivers can pro logic ii the audio to make it come through 5.1 quality (or comparable)