My thinking was if i can figure out apg on my fone i can then email myself my pgp sig and use it on my pc mate
Yeah theoretically you should be able to use the same PGP key in different software programs because they are all using the same PGP standard.
But there's only a couple of PGP programs that work on Windows because well......it's fucking windows!
The PGP standard was originally written for Gnu (Linux) and then ported to Android (similar coding), it's quite a bit more difficult to port over to windows (plus it's not very secure defeating the object) so that's why there's only a couple of programs that work with it.
You'd need Apg or Gpg on your android phone and then Cleopatra on your PC, as long as you set both programs to use the same key format all keys SHOULD be interchangable.
I'm in the same boat myself, need several programs over several machines/hardware/OS.