The fixtures used in our Wildcats are "cheap" at best. If you do find the proper washer, chances are it will leak in the near future again. I just replaced the faucet from one from Home Depot. It extends a littler farther over the bowl so I don't have to cram my hands up against the bowl to wash my hands. In the near future, I'm going to replace the kitchen faucet too.
BTW...Welcome, glad you're here.