I would go to the Dealer... I've had a local shop tell me to go to the dealer for a Tune up for my Bro's Turbo Eclipse, So I would expect no less for my car.
Just go and Say.... Gosh DARNIT I want my Tune UP NOW... I was Scheduled a WEEK ago... And I've be Waiting this Whole TIME **pound fist on counter** I wanna see the Management in this Dive.
You'll ussually get scheduled a lot faster that way.
But just ask for a Tune up ... they know what to do