Your battery is under your back seat cushion which lifts up quite easily. I bought my replacement at Pep Boys and it was $105 and the biggest battery they had. You also have to make sure that it has the side vent tubes and make sure those vent tubes are hooked up properly to vent the battery gas out of your vehicle.
Changing the battery is just as simple as any other vehicle. Hope this answered your questions.
ya, i just had to replace my battery too. I went to start my car and I suddenly lost all power. I popped out the rear seat and there was a sizzling noise so I tried unscrewing the positive post but when I touched it the post fell off. Thought it was kinda wierd that the post would rot out even tough it is located under the seat.