We had a wasp nest last summer in one of our large shrubs, by September the wasps had gone and the nest shrivelled up like a deflated balloon. As maggiebee said they have not returned this year so I would try to leave it if you can.
If you really need to deal with it, make sure you spray the entrance in the late afternoon/early evening so the wasps take the poison in on their feet that should do the trick - well that was what I was told to do by the local council - they wouldn't send someone round to deal with it for me as we owned our house (if I'd been a tenant of theirs different story) They just told me get buy a spray killer and follow the instructions