Paul, my K1 is almost a year old, and the battery is still going strong. I bought an extra one from Radio Shack for $18, and now wonder if the Kindle will die before I ever need the spare battery.
I'd suggest you ignore the battery indicator and see how long it goes. That may just be getting goofy. Also, take the battery out for a few minutes, put it back, and give it a full charge and see what happens.
Might be worth getting an extra battery just in case.