Why not rent/buy some screw jacks...jack it up to the desired height, then create small footing forms into which you'll pour concrete?

But....don't just take my word for it. You want to determine that the whole thing won't come apart as you're raising it back up....that the "footings" are as deep as they need to be...etc....

and what you're permant support "collums" etc. are going to be?

I never try to disuade homeowners from doing their own work. Many things I've seen over the years has shown me they even do better work than the "professionals" when they take the time to really educate themselves on the process involved on whatever project.

Because of the chance for disaster if not done correctly, you might think about talking to your building dept about this before you get to far ahead with it....AT LEAST. And you need to think if the entire process is within your capabilities....which they may certainly be.

A roof CAN be your friend