I think mounting your pedal on a table leg so you can use your knee is a great idea. Hopefully you know someone handy who can rig it for you. Or maybe take your pedal into the hardware store and find a creative employee who will come up with a solution that you can implement.
@ Doreen - her numbness may not be caused simply by being cold, it's possible it's caused by medical issues. My dear late father-in-law was diabetic and had numb feet.