Can't help you with the promo OST, but...
Having listened to the music from part 2 (thanks, konio755) I was inspired to track this down. I was surprised to discover that yes, both CDs from the enhanced edition (
http://vgmdb.net/album/15251) can be downloaded from FilePlanet (
http://www.fileplanet.com/191951/190000/fileinfo/The-Witcher-Enhanced-Edition-Soundtrack). Which does include the promo's four bonus tracks.
The following tracks in bold prints of OP's promo album are NOT included in the Enhanced Edition:
Tracklist:
1. Shaent Blathanna
2. Beat Them Up!
3. Old Manor Theme
4. Temerian Castle Theme
5. To Arms
6. Tales of The Witcher
7. Ominous Place
8. Clash of the Stunts
9. Golem
10. Mystic
11. Trailer Score
Bonus Tracks~
12. Born Again
13. Bring to the Boil
14. Running Away
15. They Want To Suck
I even looked them up on Youtube and no song of the Enhanced Edition has the same length as the ones of the promo album. So they definitively aren't on that album.
But I found out that you could download some them from CDPR back then:
http://www.thewitcher.com/files/music/Shaent_Blathanna.rar
http://www.thewitcher.com/files/music/Beat_Them_Up!.zip
http://www.thewitcher.com/files/music/Old_Manor_Theme.zip
But these download links are dead by now.
BUT: I tried the Internet Archive at archive.org and they mirrored those tracks :-)
https://web.archive.org/web/20060720170855/http://www.thewitcher.com/files/music/Shaent_Blathanna.rar
https://web.archive.org/web/20060105193111/http://www.thewitcher.com/files/music/Beat_Them_Up!.zip
https://web.archive.org/web/20051220081628/http://www.thewitcher.com/files/music/Old_Manor_Theme.zip
At least some of the promo tracks, I thought.
I then adapted and tried to build my own links, because the original links had an easy pattern. And that's how I found one more the list above:
https://web.archive.org/web/20070102005005/http://thewitcher.com/files/music/golem.zip
Have fun :-)
E: Found all promo tracks here:
http://chomikuj.pl/sznabek/Muzyka/Soundtracki/The+Witcher/Pierwsze