Betterer is not a real word!
Is is a word used by bogans whom believe that you can make something broken more than better.
Only a true bogan will use a word like betterer
John: Here is your PC fixed
Shazza: Did you make it betterer?
John: What the F&*K are you on about? How can you make something betterer when its fixed? You Stoopid bogan!