Oil spray under hood

while the description is not very detailed (a photo would be helpful), I will try to make some reasonable conclusions:

• There is oil all over it: Something important broke to allow a large oil leak. A large oil leak means that further operation will damage the engine.
• The engine stalled: The damage/incident was severe enough to affect the engine.
• The engine now runs again: The engine is not totally broken.
• The engine "shakes": There is damage to the engine, but there is a possibility that the damage is still repairable. Further operation of the engine could affect that in such a way that the engine gets totaled.

Bottom line: Do not start the car again, let one tow the car to an mechanic (is it still in guarantee?) and be prepared for an economic write-off.

Check with the Audi dealership, if the car is not too old and all the inspections where made by them, chances are not too bad (at least at my location) that they offer an goodwill repair.