I have a 3.0i motor 03 X5. In my experience just 2 weeks ago, I was stuck with a bad alternator. I was able to drive 60 miles with a brand new battery to get a new alternator installed. When voltage is at 11.2 that means it is running off the battery. I would replace the alternator with a Bosch or quality version soon. You don't want to be broken down. Also replace the battery, as every time the battery gets drained the battery has a reduced life.
I had a new battery from Autozone (1 year old), warranty replaced it and I bought the alternator (reman) Bosch from there too. I had it installed by a local mechanic in WV where I was stranded for $140 bucks. It is 2.7 hours labor by the book. Don't let anyone tell you its hard to do. I went ahead and had the belt changed too. I wish I would have had the oil housing gasket too since they were almost to their but I didn't have it in the car.