Hi I hadn't come across TopoR before, so thanks for the link.
Having had a look at their forum and the documentation it would appear they only have limited support for a few cad systems and can import from Spectra PCAD PADS Expedition CAD System Interchange Plus their own format TopoR PCB (.fst) (An open plain-text format for defining printed circuit board designs developed in TopoR).
Interesting to keep an eye on their developments though.