Windshield Antenna wire repair
you can try finding a kit made to repair de-foggers for rear windows, it's the same idea, conductive glue. or try radio shack or a hobby store. this conductive glue/cement is expensive, but is the only thing that will work to fix the embedded antenna.
this antenna embedded in the windshield idea did not work in my dad's brand new from the dealer 69 Cadillac Fleetwood limo and still didn't work 15 years later in his brand new from the dealer 84 GTV6. Now i have both and lousy radio reception!
good luck!
j