Leaning bulkhead foundation

My bulkhead foundation is slightly leaning in toward the basement stairs on both sides. The cement blocks are no longer sealed together well and water seeps in through the cracks. An inspector told me to dig down on the outside, then push up agaist the wall from the inside to straighten it out. He said I could use a large board like plywood to push evenly against the wall (the plywood wouldn't be left there, it is just to help straighten the wall). If I get it straight, what should I seal it with (what kind of cement or other substance) and how can I keep it from happening again (what process do I use)?