Have not seen the gear you speak of (have a R7000-2), but a couple ideas occur to me...
1) I've had great success with standard two-part epoxy glue, in repairing similar items. Follow the directions, using a minimum amount, clamp it, and give it the full 24 hrs to harden.
2) Find a *real* clock repairman, (the mall shops are usually worthless). The old guys, who sometimes work out of their own home, routinely cut replacement clock gears in brass. Could use aluminum, also.
Good Luck.