My dog bit another dog, how much should I expect to pay for the person's dog to go to the vet through court?

Ill start from the beginning... It was a snowy day and my mom had to take out my dog(a black Labrador) because I was running late from school. My mom slips on the snow and my dog(not trained to be off a leash) runs straight to my neighbor's dog who was barking at her since my mom got out of the house. My neighbor has a small dog so when they both tried to fight each other my dog obviously won beating her dog's leg before they were pulled apart. Before the bite happened my mom was trying separate them but the lady has one of those 15 ft leashes for her dog to run around. We live in town houses where everyone's door is just a few feet away and so of course they were both on public property. Anyway, my mom fell a second time before pulling the dogs apart because of that long leash being wrapped around her legs then my dog finally bit the dog's leg and my mom was able to do something at this time. The other lady is just a tad older then my mom didn't really help much except to pull her dog at the end. My mom tried offering the lady to pay for the costs but the lady just cursed her to get out so my mom just went back home. We had a reunion to go to and didn't come back till 12:00 at night and to our surprise the lady was standing near our parking spot waiting for us with another lady. She changed her mind about us not paying for the vet and starting telling us that just for the office visit it was like $400 then that tomorrow there was going to be major surgery cause the dog needed stitches for the one little bite wound that was going to cost even more money then that. My mom thought that she was just trying to get her money by now so she told her to take her to court because she wanted to pay her a fair amount of money and this way everything was on paper(no under the table deals). I did some investigating for myself and first of all an uninsured(my dog is insured btw thus up to date with vaccines) emergency office visit near my area was about 50 dollars no more(Source:Banfield: pretty legitimate vet). Supposedly they did nothing to the dog except give her a quote and it wasn't bad so they gave her a "major surgery" time the fallowing day. Second I did some yahoo answers research for similar dog bites and they said EVERYTHING even the dog cone and antibiotics was like 300-600 dollars. So how much should I be expecting to pay this lady tomorrow? Expecting the worst that she is suing us for more than a thousand dollars just for a small bit wound that the dog was jumping around after a day. The same dog that attack my dog not so long ago when the same thing happened just the other way around and did we do anything? (No! and I regret not suing her for the vet cost too!) At least now she doesn't sit outside with her dog running around our side walk on the brighter side. Any suggestions of what to say in court tomorrow to be able to reach a more reasonable cost? Again, of course, how much should I expect to pay this lady?