The two scenes of 'Ulrike' - i.e. the one of her rubbing herself off in the bathroom and the one with a friend fucking her with a bottle on a bar are both from Die geheimen Spiele junger Mädchen UNTOUCHED (X-Rated Hartbox No.11). Here is the cover:
The whole film is really hot. It can be downloaded from a notorious file sharing program, or here's a link for the extended version that was released recently I believe:
http://isohunt.com/torrent_details/46877664/?tab=summary
The only other scene that I have seen her in is the one posted above where she gets fucked by two guys on a park bench. I'm pretty sure that whole scene can be found on the 'mule. I have no idea where that scene came from, whether it was from a longer film, or what. Unfortunately, I haven't seen her anywhere else. It kills me because she's one of the hottest chicks I've seen on the internet. I've got a real soft (or hard) spot for her. I'd drink her effin' bathwater. She's soooo hot! Die geheimen Spiele junger Mädchen was released in 1999, so if she was 18 or 19 then, she must be about 26/27 now. Anyways, if anyone spots her again anywhere, please let me know!