Middlecalf,
I imagine you paid full price for your radiator--and should deserve to have one un-damaged. However, you likely will get nowhere with whoever sold it to you now that it's several months later. If it was a local dealership, it's worth a try going in person with the radiator and box. If it was shipped to you, you can ask for a discount for damaged merchandise, but less likely you will be successful.
You will hear that it was YOU who dropped it, certainly not the Parts Department. And oddly enough, they probably didn't damage it. It seems quite a few arrive at the Toyota warehouses damaged to some degree--all because the world's largest automobile company wanted to save a few cents in packing them safely. The next radiators I buy, I have decided to drive the distance and pay the extra money at a dealership, have them open it in front of me, and refuse to pay for it if it is damaged in any way. Even then, I would be curious to know if they then simply put it back in the box and sell it to the next buyer who wants one--it certainly wouldn't be the first time that stunt is done to an unsuspecting buyer.
Sorry this happened to you.