Do you have any kind of official certificate for your great-grandfather Franc Potisek? Brunadraga or variations of that placename, does not get a response on the Slovenian telephone directory. There is only one Potisek in a Draga, which is close to the Croatian border and a fair distance from Smartno.
Regarding your great-grandmother, if her place of origin has variously been given as Slovenia, Hungary and Bohemia, you have a bit of a problem here. Hungary and Bohemia have nothing to do with Slovenia. If she came from this area it is possible that she was from Slovakia. The name for a member of the Slovak or Slovenian nationalities is almost the same in both languages. The only difference is that the Slovenian language does not have the letters 'y' and 'w'. In addition, Slovakia was under the Hungarian part of the Austro-Hungarian monarchy.