My honda fit 08 (ge6)central locking device spoilt,how can i buy a new one?

Hi my central locking device which located inside the driver's door has spoilt,i have been driving without it for 5mths,everytime i want to lock the car,i have to remote lock and then manually lock the driver's door by turning my key at the door,if not,the driver's door can be opened anytime even after the remote lock,so i really wish to get a new locking device for my ride,millions of thx in advance :)