I would contact your local community colleges. Ask them if they have an "Educator Preparation Institute" or a similar sounding program.
I live near Orlando and am currently involved in the EPI at Valencia Community College. They have hybrid (meet once a week and do online assignments) and pure online courses. I doubt many would have go-at-your-own-pace, though. In my case, each course is 8 weeks long.
Website for reference:
www.valenciacc.edu/epi
Hope this helps.
I'm a teacher too, didn't major in Education though, and am in a similar situation to your wife - needing to take courses to complete my certificate.