Hi shimmer, this may sound silly but does she have an answering machine and if she does call when you know she wont be home and just discreetly say i wont be able to make the meeting tomorrow could you please find another householder, and i must say i am a little surprised that you havnt been to a meeting since november and she actually called you.
On another note your comment about the repurcussions of da, my sister drifted away quietly and was not active for over 18 months, in which time not one elder went to see her, but as soon as someone in the congregation decided to gossip that she was living with a guy they actually disfellowshipped her, so your never going to be free from their watchful eyes.