The remote is between the sofa cushions.
Not quite. The FAQ says that it uses industry standard remote commands that can be learned or programmed into popular universal remotes. That's true, but unless you have a friend with a Roku remote, you won't be able to learn the commands onto a universal learning remote. Programming the code into a universal remote requires a JP1, Pronto, Harmony or similar remote that can produce the device/subdevice header, or one that can download the Roku code from a mother ship.
If you tossed out the sofa, you might just get a replacement remote from Roku ($10) and a learning remote, learn the codes to the learning remote and put the Roku remote away in a safe place.