Despite my proclamation in my last post, I did not buy a new car battery on the weekend. The battery seems to be in much better shape now. The resting voltage reading was slightly higher on Saturday when I measured it again. I had to drive to get some dinner on Saturday evening and the car started fine in my parking garage and again when I went home after I ate. It was also fine today when I went to get groceries and ran some errands.
I still think a new car battery is prudent for the near future, perhaps next weekend or so but it appears that my car is stable for now.