You can change the width of the audio tool, by resizing the green borders. It is not possible to change the height of the player.
For more info on the audio player, please refer to the extended guide:
> extended guide, audio tool
TIP: If you want to import a CD track, you will first have to "rip" it as a wav or mp3. Browsers do not allow you to open an audio track from CD. You can do this with either iTunes or Windows Media Player.