Welcome. My name is ***** ***** would be glad to assist.
Unfortunately, there are no remotes sold that operate with the opener, due to the age.
My understanding through Sears, is that even the so called "universal remotes" will not work either sold by others.
It is suggested to get a conversion kit for the opener.
]The kit is very easy to install. The main receiver plugs into a receptacle, then you wire 2 small wires identical to your inside wall button to this receiver from the opener and wire it to the same terminals as the wall button.
Then this receiver will program with a learn button like the newer openers and no longer uses the switches.
It will have the instructions with it and there are others also, but the sears unit has a good price in my opinion.
CLICK HERE to see the conversion kit
You can use other manufacturers conversion system, they all wire and work the same way. Just search for "Garage door Remote conversion kit"
Let me know anything further or clarification needed, just reply