You have a 10 day cooling off period from a finance agreement but you would have had to sign the waiver of that in order to take receipt of the car. You cannot just take a new car drive it for 14 days and give it back without a penalty. If you look to clear the finance now you will pay back more than you borrowed as interest will be added on. Contact your bank for a settlement if you wish. But it will cost you at least a few thousand to get out.
As regards tracing a new owner there isnt really anyway i know of, perhaps someone else could help you with this.