Getting my Kobo books - how?

Not sure I've got this in the right section, hope so.

I've got a couple of books I was silly enough to get from Booktopia and they finished up coming as part of this Kobo thing: the only way I can see them is to run Kobo and look at them there.

I can't see how to get them out of it: Kobo for desktop (I have no smartphones or Kindle readers etc.. everything I have is desktop).

Can Calibre help me with this? Somehow get those books out of this Kobo nonsense?