I totally agree about the walking and taking the B vitamins to support memory. In addition, I would think Fish Oil would be very important.
There is a supplement called Phophatidine Serine (sp?). It is abbreviated as "PS." This supplement is famous for helping folks with memory. My guess is if you did all these things...B vitamins, Fish Oil, walking daily plus a PS tablet...your memory would be better in a few weeks.