You could try exporting from Quark to some format LyX will import. Or if you can export to a format that Open Office writer will open, that will export to LaTeX. Of course, with all the conversions, who knows how good the output would be.Can Quark files and/or text be opened/imported to LyX?
That said, LyX/LaTeX isn't really a DTP package. If you're looking for open source DTP, try Scribus <http://www.scribus.net/>.
rh
