It's pretty big, I was at that point before the weekend and I basically devoted Sunday to playing on it and I am pretty near the end now. So I would say you have another 10-12 hours left. Although all of this depends on the speed with which you decide to go. After all you could still do loads of subquests if you havent' already.
Actually just reading through one of the other threads it seems I am mid game and not near the end...so basically you have a long way to go
