Not sure what's available in Dutch, but what about:
Do Androids Dream of Electric Sheep? by Philip K. Dick
anything by Stephen King, if she's into fantasy, perhaps some of the Dark Tower series will be more suitable?
The Braided Path by Chris Wooding
Retribution Falls by Chris Wooding (it's about a Sky Pirate flying an airship...you could say it's the steampunk equivalent of Firefly)
Lies of Locke Lamora by Scott Lynch (I'm currently reading it, however, it does tend to use bad language)
Never Let Me Go by Kazuo Ishiguro (I've avoided the film like the plague, so I don't know what it's like, but it has a slight sci-fi twinge to it and the main character is female). When I was a teenager I read most of Ishiguro's stuff. There is some sex in Never Let Me Go, so I don't know if you feel that's appropriate for your 11 year old, but heads up anyway. I also liked
An Artist of a Floating World as well, but it's about the second world war and is set in Japan, so I don't know if it's her cup of tea.
1984 and
Animal Farm by George Orwell, if she's looking for something more serious, I read these in my teens too.
Fahrenheit 451 by Ray Bradbury
A Clockwork Orange by Anthony Burgess
For horror, why not get her into the classics with some Edgar Allen Poe and HP Lovecraft? I wonder if they do the
Necronomicon in Dutch? It's a good sized compilation of his stories. If she's into reading manga, or you want to get her started, then anything by Junji Ito is worth it, Uzumaki might be a good horror to start with, it's definitely weird enough.
