Our insurance company would not pay for any of the towing related accessories and it wasn't worth trying to sue for the losses. To directly answer your question, do you have the invoice from your original installation? The toad did not have it installed as original equipment so someone paid someone to install the hardware. That's the number you need to use and its value will be depreciated from the date of installation until now. If you can get anything, it will not be a replacement cost but rather the original cost less depreciation.
Good luck and I am sorry to hear about your accident. Just hope everyone is OK.