You can try Ebay and get a second hand one most of them are Pre-Facelift anyway. Or ask Sere Motors (there's a guy here whom i cant recall the name of...) who can give you a quote for a new one.
i wouldn't recommend getting those Fibreglass type from Aftermarket companies if a Deer incident happened again (God forbid) it wouldn't handle impact as well and more damage may be done.
can the bumper not be repaired anyhow? BTCC bumpers don't come cheap.