It looks like the battery is at the end of its life. Mine charges within a couple of hours. For normal use (as a remote not uploading or programming), I can have it out of the docking station for a few days.
You could try cycling the battery through a few charge/discharge phases just to see if it has been unused for a long time. If you do not get any improvement in battery life then I would replace the battery.
I knew this was a mistake; my grip on reality's not too good at the best of times. Glitz, in "The Ultimate Foe"