This is a bad situation for your doggie! Bengals are highly territorial. Mine stalks an outdoor cat that I let in the house to nap. There may be a couple of solutions here.
Talk to a cat behaviorist. See if there is one in your area and some will even Skype with you. It would probably be better to have one in your home to analyze the situation. It's not as easy to sit miles away and diagnose the solution.
Do you have your home catified! Cat trees, shelves, scratching posts, toys, cat beds? The more you have for your cat, the less likely to attack a poor dog. A cat normally prefers being high off the ground to observe everything around them and your dog cannot climb a cat tree. And bengals cannot get enough play time.
Try Jackson Galaxy's Spirit Essences website:
http://www.spiritessences.com and see if there is a remedy there that might help.
The next thing is to STOP SPRAYING WITH WATER. It does not help and only compounds the situation and gets the cat stressed out. Would you like someone spraying water in your face?
My last thing is to watch a few episodes of My Cat From Hell. I am sure there is at least one which has dealt with a cat terrorizing a small dog. Check the Animal Planet website or google the name of the show. Seriously. If you truly want to find a solution to this problem without getting rid of your cat, you're going to have to spend some time researching what will work.
The other thing may be to create an outdoor enclosure for your cat. This can be portable or permanent, small or large. Make sure your dog cannot get out there. Your little Yorkie must have some peace in her life. The poor thing. Know that YOU are not doing anything wrong here. Some bengals get along with dogs; some do not! Something has to be worked out with your bengal to be less aggressive.
Good luck and keep us posted.