You need to speak to an attorney right away. There may be several issues such as (1) was the individual an employee or independent contractor (2) whether his actions were within the scope of his employment? Hiring an attorney will potentially save you a lot more money than a money judgment against you would.
More information is required. What are the facts that underpin the negligent hiring claim? You should know by now given the case is going to trial in October. You absolutely should engage a lawyer to represent you immediately. You may have defenses you don't know about. Scope of employment does not necessarily mean the threat had to happen on the job. He was introduced to the victim through your company. How did he het her name and tel no? From where did he make the call? what is his background? what screening did you do before letting someone into a customer's house? Get a lawyer asap.