The electrical motor is/was manufactured in the US. The manufacturer refuses to sell the motor due to an airtight contract with Audi. I know because I called them and asked. They wouldn't even sell parts to it. Your best bet is to find a junk yard and pull the whole assembly. I got a back up for $100 and if you can get one, buy it. If you have taken it apart and are sure that it is the electric motor, it can be fixed. The big problem is that the brushes are not designed for replacement, and that is probably the problem. If you are looking at the armature, check to see if brush material is packed in the commutator groves. If so, clean them out. (That was my problem). You can even take a fine xacto hobby saw and recut the grooves, but that is risky. If the brushes are totally shot, you will have to cut the mushroomed rivits for the brushes, drill a hole for a screw, tap it and fix the thing.
Now, if you are guessing that its the motor because the top doesn't work, search the forum and you will find many posts on this. Read them. I am the only poster who has had a bad electric pump motor. For everyone else it has been wiring. Understand that there are electrical and hydraulic components to the system.