Please tell me this is a mnor problem

We bought a 2002 Prius last year to replace our murdered Toyota Echo. We love the car, but this triangle of death is driving me nuts! The lights came on again last night so while my husband was taking it for an oil change today, he asked them to do a diagnostic and came up with error code P3011 Battery block 1 is weak. As I've been checking the forums, I've noticed everyone with a battery block error seems to be getting multiple error codes, but we just got the one. Is this good news for us and our poor car? And what should we do next? The dealer we bought the car from has hybrid certified mechanics, and we plan on calling on Monday, but we have a vacation coming up that can't be canceled at this point so money is tight. Is it possible it can be a minor adjustment? (fingers crossed)...

 

Thanks for the advice. The lights for this problem just came on last night, and I have no intention of letting it go. I know the guy we bought the car from had mentioned replacing single cells in the battery, so I'm betting he could do it for us, and when he quoted us a price for the catalytic converter last month he was very reasonably priced, so I feel he'll be fair. We'll need to try to get it to him on Monday. Keep your fingers crossed for us that it's not the whole battery!