How was the new dog introduced to the cat? Was she brought into the house and introduced slowly to the cat or was she put down and the cat had to deal with it? Jack was/is likely "protecting" Jill from that mean, nasty cat.
(added so as not to be misunderstood as to my meaning)
Now, you have your work cut out for you...........
You need to ensure that every room where the dogs have access to there is a place where Patch can get up high; be it the top of the fridge, a tall cat condo, on top of your curtain rod; anywhere where Patch can go and the dogs can't. You need to learn to control the dogs when around the cat by correcting the dog(s) every time they lunge or bark at the cat. It would not hurt to start from the beginning and do things properly so Patch can feel at home in her own home. Poor baby must be so confused.
Here are a few sites for you to read. Maybe you'll find something helpful and useful in them.