I'm not a stucco guy but I've done new construction enough that I know the stucco guys purchase all the styrofoam detail stuff including the columns. I don't know from where, but all that suff is delivered. Then they put it together on site with a special glue that comes in a spray can. Ask a stucco guy or try a building materials place or wherever those guys buy their material. It shouldn't be that hard to track down with a little legwork.