You can go on eBay, type in polyurethane bushings. About 3/2 the way down page 4 you'll see some bushings probably close to what you need. I would suggest clicking on the logo for the eBay store Never Enough and contacting them. You will need to know the diameter of your sway bar and they could probably fix you up. By the way, we had a similar problem front and back: missing bracket, missing bushing, unattached bushing. I went ahead and purchased new brackets as well, and installed everything myself. Good luck.
Butch and Peggy
N.Central TX; 2000 Itasca Suncruiser 32V; Workhorse P-32 Chassis; 7.4L Vortec V-8 w/Banks Pwr Sys; Steer Safe; Springs/Airbags front; Timbren Suspension kit on rear; Onan 5K