I replaced mine couple weeks back, I found it on Ebay.
The process for replacing it is fairly simple.
Once you remove 4 screws, underneath pads. (One under each pad)
Grasp the bar(stand) use you thumb underneath antenna and push apart.
Two little catchers on top and two on bottom.
Once open, the battery is under. The main control bord.
After removing the 4 screws that hold that bord down, if your careful you may get away without unplugging the antenna. I did on two different occasions. Once had to. They can be tough.
The clips holding battery in place can be released using flat screw driver.
Hope this helps.