Hi, Monica, try Vbelt Supply:
The link above takes you to a page that has belts 1.25″ wide and over 100″ length. I forget, I think my 8×12 uses a 120″ belt for the flywheel. If you need to do any calculation for belt length vs press speed, I treated this some time back on my blog.
gary // Paper Wren Press
http://www.paperwrenpress.com
http://www.paperwren.blogspot.com