Is the key totally broken off in the ignition or does the remains of the key still turn the ignition switch and start the engine, if so a lock smith may be able to extract the key. The steering wheel cowling/trim panels need to be removed. There is a detent to prevent the switch from being removed without the proper key in the ignition switch. Check out the website official kia website www.kiatechinfo.com/ they have workshop manual information on line for free. This is probably a job best left to a locksmith or garage.