Bike Chick,

At your next PT appointment, ask your PT specifically what tests he or she can do to get a clearer picture of what the diagnosis is. It is quite possible to get a reasonably good impression of a IT Band syndrome (bursitis is usually secondary to this) vs a labral tear. If he/she can't give you an answer, or gives you some sort of vague answer that isn't really an answer at all... you may want another opinion.

Go get a really good deep tissue massage and have the massage therapist work a lot on your Glute max, glute medius, glute minimus and TFL. You may also be tight through your low back area (most likely L4-5) and some work there will also help.

Get on a foam roller and work your hips out as much as you can.
Foam roller techniques for the hip.
The thigh.

And stretching is key. This is a reasonable routine for stretching the hip/IT band complex.

If you get on these things now and you respond well, you can be ready to run your marathon in January.

It would also be very helpful to do a running form analysis with a qualified PT. That should be done after your marathon and recovery period. You shouldn't try to change your running form drastically right now.

Finally, even if you do have a labral tear, it is quite possible to continue running. I have a labral tear too and like Yellow, I still run distance. I also work with people following arthroscopic repairs to the hip and I have seen many do very well and go back to running.