Hi, Phil,
You've got a problem here. Your only solution is to check on the internet to find a company that will unlock your radio and allow you to set a new code. There's plenty of them around. Just go into Google and type in 'Unlock car radio'. Give it a try. There may a company near you that will be able to do it. Give any car electrician in your area a call..find their number in the Yellow Pages. If they can't do it, they may know a man who can.
Best of luck.
Denis Langley (Car Aid Mobile Mechanic), September 2008