I really don't know that the problem IS the connector, but it might be. I am unsure if you can get the sensor or the connector for the Crossfire - but the SLK320's sensor and connector are the SAME ITEM.
You might search for "ambient" or "outside" temperature sensor and connector for the SLK320.

THere is, of course, always the local salvage yard - look for a car that was rear ended!