you can go to weheartit.com and type this on search box "female ulzzang". you'll see some good and pretty ulzzangs that you can use as your oc :D hope it helps :D

there's actually a shop here in aff that provide all ulzzangs in which you can find so many OC :)
http://www.asianfanfics.com/story/view/105090
that's is just one shop.. there are lots here ... hope it helps. ^^

I have the same ullazzang on my computer, I think I found her when randomly clicking on names, at an ulazzang shop.. sorry I can't help more.. >.<