With spross's help, the downstairs toilet here at the house is repaired. I've been able to manually flush the toilet using a small wooden dowel to raise the actuator, as the chain piece had snapped off, but I picked up the chain and grommet that were needed for this, though I didn't have the dexterity to do it, not to mention I can't bend very much due to the pain in my back. spross dropped over this afternoon and took care of the threading and installation, so the downstairs toilet is now properly functional again.
I am relieved, in more ways than one. :)