I found my curved shears at Petsmart and I think they also had thinning shears. You can also order them from PetEdge...
Wholesale Pet Supplies, Dog Grooming | PetEdge.com Be prepared though, they are a bit awkward to use until you get used to them and until you learn just how your dog's hair lays. What I 'think' it should look like when done isn't always the case

but, I'm still learning and hair does grow back!