Then, it is up to you to decide (1) to discuss with your boss and the finance vp face to face, in the constructive, supportive manner, to find a solution. MrsD's incapacity is already known to the vp. so be prepared that you may have to spend time, like it or not, not only train her but follow on her for a period of time.
(2) to escalate to the president if you insist this is not your work and refuse to do the extra. I will definitely not recommend it though. Your president would hate you for bringing these petty problems to him.