Sounds like you've figured out which way to go with this. I agree, sending her an
invoice for the time already spent makes sense. You did make some changes on her computer and have offered to make future changes if she is interested. She seems to want to get two services out of one person, installation and teaching.
I doubt she is going to find a teacher willing to install or a tech person who installs, willing to take the time to teach. She's just going to have to bite the bullet and pay multiple people for all of the things that she clearly needs.
Your time is important and she owes you for that hour.