Heheh buba Švabe :D Well they were called both Švabe and Nijemci or Nemci. Nijemci or Nemci was and is old Slavic word for them in general, and means "mute" people. Pretty simple, we didn`t understand them :) . Švabe is regional name, which later was name for all Germans, no matter from which part of Germany they did come. It is not so unusal, that regional name for specific group of people, later become the name for larger part of people.

Well, Actually Nemci is thought to have been used for all foreigners as it means "the mute ones" (in the sense "the ones who don't speak our language", oposing to Slovani, the people who speak, the people of the same word – though this idea isn't definite or completely recognised), but since we kind of had a lot of contact with Germans this name settled for them. Hungarians took word Nemci from Slavs aswell and Hungarize it a bit – it's still recognisable though.