Apple has posted information about iPad battery Replacement Service. Apple will replace your iPad battery for a service fee of $99 plus additional $6.95 shipping amounting to $105.95 per unit plus applicable local taxes.
However, instead of swapping a new battery into a customer’s existing iPad, “You will receive a replacement iPad that will not contain any of your personal data”. As such, before you submit your iPad for service, it is important to sync up your iPad with iTunes to back up your contacts, calendars, email account settings, bookmarks, apps, etc. Apple is not responsible for the loss of information when servicing your iPad.
You can arrange battery replacement service at your local Apple Retail Store or you can contact Apple Technical Support. It takes approximately one week to complete the service from the time you send your iPad to Apple.