I don't think the local congregation would pay anything out of pocket - they probably have an insurance policy (and I bet the WTS requires they hold one) that protects against incurring any out-of-pocket expenses. After all, whos to say that a non-witness visitor doesn't accidentally slip on the driveway outside and crack his/her head open? Witnesses aren't allow to sue other witnesses, but in this situation, its entirely possible to get sued, and the WTS is usually pretty good about covering all their bases financially. You may have received some money, but I don't think it was the money of the local congregation or the WTS. I'm not saying it wasn't worth it, though. If this accident cost a lot of money, then it was good you were able to recover at least some of your costs. That's what insurance is for, after all.
MeanMrMustard