Replacement Delta bath faucet/diverter

[rangerbob86]

Probably a dumb question, but I'm trying to replace my faucet since the diverter stopped working. I unscrewed the current faucet fairly easily, but am not sure if I am supposed to leave the plastic adapter attached to the wall or not. I'd love it if I could find an exact drop-in replacement (I know it's a Delta). I tried a universal fit one from a big box store which was just barely too small to fit on the existing plastic adapter. Any help would be appreciated...here are a few pics: http://imgur.com/a/az8gF

 

[Matt30]

Email delta about a replacement. They may cover it under warranty I have gotten a few of them for customers when theirs buggered up.