Curtis' wheel nut remover is the best option here, it's cheap and you can't use the nut again anyway as you don't have the key, you can sell the set on when you are done with it
By the way...using the tool that i have suggest WILL allow you to reuse the nuts if you happen to find the key as it puts a thread on the outside of the nut...thats all, just that i wouldn't look as nice...!