I would first use a blower (hand bulb variants, like Giottos) on it to see what comes off. You can also clean this yourself with many different options out there. Patience is a virtue here, take your time if you clean this yourself. It is not difficult, it is just a bit tenuous. Don't be scared by all those that would dissuade you, I suspect a vast majority haven't even tried it themselves. I have used 3 different methods with success in the past on a variety of bodies. However I always first use a blower, it seems to do the job about 90% of the time.
That being said, there are many professional cleaning opportunities, just make sure you are aware of their warranty, and take a test shot of a wall at f22 right before sending it in as a baseline, and supply a copy with the camera. If they do any damage, this will be your insurance policy that it was them, if they were to say they received it that way.