I would keep trying to reach the treasurer for a few days. Call, email, whatever way you have to contact her. If after a few days you still haven't heard from her, then check your bylaws. My guess is you'll have to hold a special election to replace her. You may also have to do something to remove the old treasurer from office, since she was elected. I hope everything works out!

election were done, treasurer was voted in but wasn't at meeting,
check with her before the meeting, to see if it was ok to nominate for treasurer,
now she is not returning my phone calls, the previous treasurer said she can cover it for another year, what to do?