Datejust Date Wheel Problem

[Shulaw74]

I just got back from vacation, and went to fix the time and date on my Datejust. When I pull the crown out to the third position, it sets the time as it's supposed to. After winding it in the first position to get time moving again, I pulled the crown out to the second position to set the date. I turned it and the number started to move, but stopped in between two numbers, and now it no long moves. No amount of finite pushing or pulling on the crown advances the date wheel. Does anyone know what might be wrong, whether it is serious, and how much it might cost to get it fixed? Thanks.