How to order a battery pack for my MacBook Pro

Hi,

Here is a link to a replacement battery that will work with your Laptop: MacBook Pro 15" Retina (Late 2013-Mid 2014) Battery

It includes all the tools you will need to perform the repair yourself.

Here is also a link to an ifixit guide on exactly how to replace the battery using the product in the above link: Sostituzione batteria nel MacBook Pro 15" Retina Display versione fine 2013

Please note that if you are careful and confidant in your repair abilities, you can probably skip removing all the components from the housing and just jump straight to the removal of the battery.

I hope this helps, let me know if you have any further questions : )