On LS, there is a castle along the road south of the Compassion Desert, on the west side of the swamp (all of this is east of Britain, just follow the road) which has most of the armor sets on display on vendors. There is also a house in Tokuno west of the Homare Moongate (on the south side of the road) that has them also displayed on vendors.
As for the Virtue Armor there are eight pieces
Helm, Gorget, Tunic, Leggings, Arms, Gloves, Shoes, and a Cloak. The cloak has a specific quest to get, all of the others pieces have a chance of dropping in your backpack when you fight monsters in the anti-virtue dungeons (Shame, Destard, etc..). It is a random drop with the other virtue artifacts. You can try trading with someone or purchasing the other pieces you are missing.
Stayin Alive,
BG