How to have a battery replaced on my mid 2012 13 inch MacBook Pro while living in Ecuador?

We live in Ecuador and I have noticed that the battery is losing its charge faster than it used to. Is there any way to purchase a new battery and have it sent here?

I also have an older 17 inch MacBook Pro that I was able to replace the battery before we left the States. That one was easy, just open the battery compartment and change out the battery. No big deal.

I am capable of working on my 13 inch MacBook Pro as I have already upgraded the memory to 16 GB and also replaced the standard hard drive with a solid state drive. My problem here is there are no Apple dealers here in Ecuador and I can't find anywhere here on Apple's site to purchase a replacement battery.

Any ideas on fixing the problem?