Hi Marcel, Do you have access to a windows computer with Photoshop? I myself use flyerwire.de for flyers created with inkscape. So what I do is export to png from inkscape at 300 dpi (don't forget the bleed) and open in Photoshop to convert to cmyk (watch out for transparencies. If you have any add a white layer underneath and flaten first before converting to cmyk) and then save as jpg. It's a pitty, really, that gimp doesn't support cmyk colors, because this way I have to boot windoze.
Hope this helps! Viel Erfolg! David
