if the electrolyte level was that low for a while, sometimes the electrode plates will just be fried. you can fill it up with distilled water, then charge it over night (or get a jump and drive around like hell to charge up the battery), but - in my opinion, it probably won't hold a charge again. It looks like cashing in on the pro-rated warranty for a new battery. But you could get luck and have it be OK after filling/charging. See if it starts again tomorrow, then keep an eye on it.

For your info, after shopping around (volvo dealer, pep boys, sears, etc) I went with the Interstate brand battery (by Johnson Controls, much like most of the name batteries).