I"m surprised that your local dealer won"t even order the parts for you...you"ve made their life easy by having the part numbers even, all they have to do is cash your check!
You might have to do some searching in your local area for scrap spreaders to rob parts off of, but you might find as I have that the parts worn to nothing on those spreaders are the same that are worn out on mine.
The 217 is for the single beater in the back, what size box do you have? 212, 213, or 214? I have a 213 with 217 beater that"s next on the fixup list.