electric windows

I set off earlier today and hit the down button on the window. The window went down about a 3rd of the way and then stopped and started to make a crunching/grinding noise. I sent it back up which it did fine until it got to the top and then a loud clunk.

I pulled the door card off to find a large ish cog sat in the bottom of the door. Im presuming that its broken off but how do i get the motor out to see where it goes back?

By the way its a td5 not a 300tdi as my name sugests!