The 2nd one is crazy expensive, but it has the snap on feet (the snap in stitch-in-the-dich foot is great). Shop around though. I got mine much less than that at a local shop when they had a 40% off sale. At least these will give you the Viking part number to search. Try ebay also.
http://www.sewingpartsonline.com/wal...123573-01.aspx
http://www.sewingpartsonline.com/dua...20219-096.aspx