Hi, check out the electronic kit manufacturers and suppliers, you need a simple garage remote control kit.
It will have everything you need.
Tom.... 
search.jaycar.com.au/electronics/Garage-Door-Remote-Control
check out the 433Mhz kit
Hi, check out the electronic kit manufacturers and suppliers, you need a simple garage remote control kit.
It will have everything you need.
Tom....
search.jaycar.com.au/electronics/Garage-Door-Remote-Control
check out the 433Mhz kit