As I understand, you have already completed the Femi's total disassembly. Did you investigated her power subsystem?
Does all 6 AA's simply connected in series (9v), or there are 4 AA's (6v) for motors and 2 AA's (3v) for brain? Personally, I think it's the second case, but I'm not sure.
I'm thinking of adding an external power jack and if needed, two integral voltage regulators for 3v and 6v somewhere in her boots (I hope, her motors consumed not more then 1A in maximum, so 7806 will do for 6v). So, if not wandering, she can be able to run on mains, thus reducing my battery expenses. And if a power jack is pulled out, she must switch to a battery power.
But I'm slightly afraid of accidentally burning her out...