Skip the dealer. Find a reputable independantly owned and operated shop. While intermittant problems can be hard to diagnose, there are things that can be checked. dealers often aren't interested in spending the time necessary to troubleshoot 11 year old vehicles. They'd rather you replaced it with a new one.
Other than what a tow truck can do, there's little a traveling mechanic could do. without having one's tools and diagnostic equipment, the limitations are severe. It's even difficult to work in an unfamiliar shop. One spends as much time trying to find things as fixing the vehicle.