Nah its not a dumb question so dont worry.
Generally for all manga that get licensed and translated like this it seems like amazon has them all, obviously untranslated probably wont be but.
Link for the lazy (The entire girlfriends series was divided into 2 big manga)
I actually really like the slow burn, so that's nice. Is this the one? Deciding whether to just get the kindle or plotz down the munny for the set in paperback.