I found the track bar (which includes the bushings for that) on Rockauto.
http://www.rockauto.com/en/catalog/f...track+bar,7500
The part number you give is for the rear axle assembly......I have not found a diagram for it......but I got a hit in the link that I am putting below......for the whole assembly......they don't seem to list the bushings.
https://www.fordpartsgiant.com/parts....html?PNC=4264
My google search on the part number did not bring up much......though it did bring up this post.
I found a diagram on fordparts.com
http://www.fordparts.com/Commerce/Pa...model=Windstar