They are cut to a certain pattern so borrowing someones else's generally wont work, most manufactures have over 100 different patterns.
Most garages have a set similar to this http://www.ebay.co.uk/itm/4pc-Emergency-Locking-Wheel-Nut-Remover-Tool-Removal-Universal-Set-FLASH-SALE-/121628875997?hash=item1c51a55cdd:g:AZgAAOSwBLlVNgJv
Not sure what they would charge you to remove the locking nuts though and locking nuts will be damaged removing with these tools.
Maybe contact previous owner and ask if they know where the tool is, maybe they have it somewhere safe and forgot to leave it in the car.