You can not sue for damages that have not yet occurred. If they damaged your fence, you can sue them for that. If they damage your cat, you can sue them for that. Call Animal Control (which is usually the county) and report these incidents, and every incident thereafter. Sometimes they will get involved if they see a pattern that the dogs could be dangerous since you say their intent was to attack.
A dog's owner is responsible for all harm it causes not under the owner's control. Your problem is that the dog is still on its property; NOT yours.
You may wish to consider a kennel/cage for your cat. It can get fresh air and exercise with no danger of attack from dogs, etc.
The foregoing is for general information purposes and does not establish an attorney-client relationship.
I'm a little confused as to who lives in the house. Do you live there, too? You could probably sue under a general negligence theory.
This is not to be construed as legal advice. I do not have an attorney client relationship with you.