Ok what you need are hub rings. they are plastic inserts for aftermarket wheels to shrink the wheel hub to fit the hub of the car. and you are correct about they do come in 4x100. if you can order them from
Discount Tire, Custom Wheels, Truck & Car Rims | Discount Tire
this is my work. if you dont have a discount tire near you this is the best way to go! if you have anymore questions you can pm me!