you can do it yourself, is very easy, the instruction is in your owner manuel.

 

Yes
Simple to do
Open it, get number off battery and replace with same number battery
Available at most drug stores or places with decent selection of batteries
Its usually a fairly common battery

 

Yeah you can change it Oldtimer... Walgreens or like a Batteries Plus has them in stock. Just take ur time popping it open bc the fobs are pricey is you bust one