Garage: water and mould

Have a garage below our house, two of the walls are against the ground, one of it has moisture seeping through. This wall is partly against the driveway, so moisture is seeping through badly. Paint is all bubbly and powdery. It's causing mold in the garage. Can't see it much on the walls, but books, car seats, etc all are picking it up. Lost some valuable stuff this way.

I plan to strip the walls, clean out the garage and repaint. Want to add a protective, but hopefully cost effective, layer of something under the paint to stop it. Was also told to put something on the outer wall to prevent it, but that would entail digging up my driveway and rather not.

Any advice would be highly appreciated! Tried searching the group, but wasn't successful.