The 22-year-old was discovered in the upturned Honda Odyssey on scrub land behind a building on Gorge Road, at about 10.30am on Wednesday, March 13.
Officers believe the car left the road, went down a bank, and crashed into the building some time between 3.45am and 6am.
They have identified and interviewed at least one other person believed to have been in the vehicle when it crashed.
Sergeant Steve Watt, of Queenstown Police, said: "We're awaiting the results of forensic tests to determine who was driving the car when it crashed.
"The girl will likely be in hospital until June, before being airlifted back to Germany. Her family are with her.''
Police have appealed for CCTV footage from local businesses to help in their investigation of the serious crash.
Meanwhile, charges are being considered for the driver of a white Toyota Hilux ute which crashed off Peninsula Road, Kelvin Heights on Monday, March 25, at 1am.
His male passenger was seriously injured and taken to Dunedin Hospital in a critical condition but is now stable.
The ute appears to have hit a speed sign before careering 20 meters down a bank. The driver (25) managed to climb back up to the road and flag down a passing motorist. The passenger was found outside of the ute.
The driver has been blood tested and police are awaiting the results and also the condition of the passenger before determining charges.
Anyone who witnessed either crash can contact Queenstown Police on 03 4411600 or Crimestoppers anonymously on 0800 555 111.
