I have an iPad 3 / 64 wifi only that still runs great, but I am pretty sure the battery is starting to deteriorate. My iPad is no longer under warranty or AppleCare. I've read that you can purchase an out of warranty battery replacement for $99 from Apple. Paying $99 bucks to ensure my battery won't render the iPad useless for a another year or more is worth it to me. How does one start that process ? I live 250 miles from the nearest Apple Store, but will be near a store in Phoenix in March. Can I just walk in and get the battery replaced on the spot ?