That font may be usable for Esperanto with modern software, but would it be usable for Esperanto with Quark 5? Almost certainly not, I would presume. You would presumably need to modify it, replacing some Latin-1 characters with the Esperanto characters. That modification is probably not hard to do, when you know how; I think I may have done something like that myself, a long time ago. The number of people interesting in modifying fonts to use them with pre-Unicode software has probably rather dwindled. You may need some kind of computer archaeologist for this!