Well if you try looking for Apprentice Alf via Google you might well find tools that would handle DRM issues with ePubs and Calibre.
If not, you can still add the ePubs to Calibre and transfer them to the Kobo; you can't however make use of the facilities of Calibre to change them to other formats.
Also, for the books that were already on your Kobo, I don;t think you will find them in My Library at koboreads.com and thus, will not be able to get an ePub version of them
