Hi, you would have to contact your local Xperia Care Centre to get a quote on this.......an alternative is to go down a 3rd party repair shop tho this would void any warranty from Sony if indeed you still have some, or you can change the battery yourself.....there are many videos on how to do this DIY task :smileysmileywink:
http://www.sonymobile.com/global-en/support/contact-us/
