First, what do you mean by a "judgment hearing"? What is scheduled?
Second, you've waited a little long to ask, because the price went up when they had to spend money to file.
Third, now you're better off talking to the attorney than the CA, because he/she is going to have to carry the work from here.
If you're going to do that, start yesterday, because calls will have to go back and forth to get authorization, if there will be a compromise.
The answer to your question will be "the whole thing, including costs and interest", so don't look for a set percentage. Figure out what you can realistically offer forthwith and follow-up. Then figure out the reasons that should be attractive to them without the necessity of spending more money to enforce a judgment. The justifications are innumerable and you haven't given enough information to work with in the time available.
I've been away from this forum for about a year, but DebtCollector used to have a very nice by-the-numbers checklist for handling negotiations, if you can get that far. See if you can find it using the "search" function and have it in front of you, if you get a chance to try.
The amount involved will get much bigger, if it goes through judgment.