Help with replacement throttle or parts?

The bike I bought this year has some aftermarket aluminum grips. I was doing a bit of cleaning and I saw that the push-pull ring with internal teeth was split between the cable ends. The throttle still works without problem, but I just want to fix it.

Does anyone know where I can buy just the ring (for now)? Or should I just replace the whole grip?

If I replace the whole grip, do I need to get a throttle tube? This is my first grip replacement...

I have a 2001 5th gen with the stock risers.