Athena

I found a 2007 Nissan Altima Hybrid and purchasing a hybrid is new for me. The car has 94k miles and the dealer is selling it for $12,500. I have test drove the car and I Already I know I would have to negotiate the price because with all the options of GPS, XM radio, heated leather seats, back up cam, 6 disc CD changer, and a few other things, I found its retail value in good condition is $11,900. But my major concern is the battery. With the car being at almost 100k miles I do not know if the battery it's self has a warranty. Because the dealer said I would have to purchase a warranty for the car. Do you all know if the batteries in these cars start to go around 100k? Or if I would be ok for another 50k-100k miles.