For those who missed it, the full version of the lullaby was released (thanks to @Kinley). Author: Marcin Przybyłowicz.
See more info on the Wiki: http://witcher.gamepedia.com/A_Night_to_Remember
Thanks to @Kinley and @mecha_fish for lyrics reconstruction.
Excuse me if this is a little bit off topic, but do you or anybody else have any idea how or where I could download the legal high quality audio for this one in English and Polish, and also the English, Polish and Japanese version of "The Wolven Storm"? I wouldn't mind paying for those. Thank you very much in advance