General Advice - Hybrid battery and AC

Hello everyone.
I'm just a little worried and was wondering if some of you might be able to offer me advice.
In short... I'm worried my Hybrid Battery might be on it's last legs.

I don't drive it much - Once a week maybe where I take it out to a local store, and I'll even just drive around for 20min just to keep a charge on the batteries.

It seems I rarely see the Hybrid charge meter going all the way to the top. It's usually low by about 2 bars.

In the summer, when I turn my AC on the bars drop pretty low - around half way. I can get it to charge back up (again about 2 bars short of full), but it seems the next time I use the car the charge drops back down again (in about 5 days or so).

Basically I'm just wondering... is this normal? Is it just showing signs of age at this point and I should take this as a warning that it might be on it's way out? Is there any way to test it to see how good (or bad) it is?

Lastly... is there any sort of other warning signs before a Hybrid battery fails? I'm worried about just coming out to start the car one day and getting the dreaded "!" to say the battery is dead.

Thanks for any advice.