Roof on frame extention

I have a one story 5 X 20 wood extension on the side of house. I would like to allow as much light as possible in to this extension via the roof. So I can then channel this light to (future) windows/ glass panels on side of house. This will allow my garden level floor to have light. It is so dark that I have to turn on the lights to see even if it is broad daylight outside. The real question should I use a series of skylights or are there large glass panels I can install in place of the entire/ part of the rubberized roof. Thank you for your suggestions.