Try Google.

The recoil pad on the rifle is a Sims Vibration Labs Limbsaver. There are a lot of online dealers. I bought mine locally. The 'over the shoulder' recoil pad is a Past brand Mag Plus model that is reversible for righties or lefties. Also a lot of online dealers but I bought mine at a local shop.

I see both of these on e-Bay from time to time.