Hi There! I have the same machine. What does this part do? You could contact your local sewing repair shop and ask if this piece is unique to this machine, if indeed they don't make it anymore. Check to see if they have the part used or try E-Bay. Try to find the part number. Good Luck! AK
Also, try this link http://www.sewingpartsonline.com/race-cover-viking-4116662-01.aspx. Beware with Viking though, that they are inconsistent on their part numbers(different part numbers for the same part and misprints in their catalogs), I've had even the sewing shop order the wrong part because of this. Also, the part is probably not plastic, rather nylon.