im not an expert but i accidentally snapped my fiat bravo 2001' key in half.
I phoned up the AA and the genuis from AA welded the key back together so i could make it back home as i was stuck 200 miles away from home.
Luckily i had a spare key at home.
But if you dont have a spare key i would do the following.
go to a car key cutting place (most usual key cutting places should do car keys with transponders). Ask them if they will be able to use their genius skills to weld the key back (or anything else in their expert opinion) so they can use it as a template to cut a new key with. then they can just use the same code from the old transponder and eletronically copy the code to the new key.
or if the key has not snapped in half like mine did then they should be able to cut a new key and copy the transponder code over to the new key. even simplier!
and vola you should have a new key that works!
Should cost around £30.
I know a shop called 'hi-heels' in sutton, surrey that cuts transponder car keys aswell as another shop (which ive forgoten the name of) located at the top of sutton (surrey) high street located just by the train station.
hope this helps!
DRU. J, December 2008