Well, I went to Tractor Supply Center (TSC) today and all they had were imperial sized pulleys (1/2" and 3/4" bores). The motor that I have must be a metric size one because the 1/2" hub pulleys were too large. I bought some 1/2" hub pulleys anyway since I wanted to see if it would work as a proof of concept (and just around how much more power I'll need).
Now I just have to make a mount for the motor. I think I'll just use a piece of 2x6 wood that I have laying around and make a simple mount.