Go buy a cheap socket, CAREFULLY hammer it on over the old wheel lock and then see if you can get enough torque to use a ratchet to get it off.
If not I saw a kit from Pep Boys that has teeth and is designed to work the sme way but has teeth designed to cut into the wheel lock and get it off.
Thats how we got the locks off of my friends Mustang. The previous owner lost the wheel locks.