I think I'd probably drop it. She needs to get more organized.
I would, too, but the OP DID last say to e-mail her if she wants to reschedule.
SNIP
Yep, I said the bolded above. I sort of regret it now, but it was in the spirit of giving her the benefit of the doubt. In hindsight, I think the fact that I said it locks me into rescheduling with her.
Okay, I'll go with the thought that you are somewhat, sorta, kinda locked into rescheduling simply because you made the offer.
I completely agree that if/when she e-mails you asking, yet again

for your help, you make an appointment that best suits
you. You've already tried to accommodate her schedule. Didn't work.
Which is why this idea the best:
Why don't you schedule a conference call. That way you can be at home working while you are talking to her and you don't have to leave your house and interrupt your work day
Is there a reason that you have to do a face-to-face?
eta: Most definitely wait for her to contact you.