Go to your local auto parts store, Walmart, or similar and buy a car cover. Any car cover that will fit (even if its not for a Boxster) will work until you can get it repaired/replaced.
Or go to a hardware store (Harbor Freight) and buy a tarp and tie it over the car with some rope.
Or buy 6 packages of plastic wrap from the grocery store and .... no, don't do that, I'm just kidding now.