You made me go out and pull the bolt. Its a metric 8mm coarse thread flange head bolt 122.8 mm long. The body of the bolt is slightly smaller than the thread diameter and the tip of the bolt has a partial taper point to help align the compressor to the engine bracket.
Might try going to the wrecking yard since this is not a standard bolt but a factory bolt made for the application. Still available at the dealer last time I checked a few months ago.