I did some looking around and found someone that got it working : http://regexadvice.com/forums/thread/52271.aspx
Using : (?P<author>((?!\s-\s).)*)\s-(?:\s(?P<series>((?!\s-s).)*)\s-)?\s(?P<title>.*)
It will identify correctly :
Warhammer 40K - Atlas Infernal.rtf
Warhammer 40K - Bastion Wars 01 - Emperor's Mercy.rtf
Since i think many people have used this in windows, i'm posting (a bit out of topic).
Please forgive me for that