First off Welcome to the T/A forum, always good to have someone new stop in. Please feel welcome to come back often.
As for the engraving, check with a few of your local gun dealers to see who they recommend. Another place to try maybe a jewelry store (however I would not take the entire pistol in, field strip it and take in only the needed pieces). Could also try doing a Google search for an engraver in your area..
Make sure that the serial number stays nice and clean also.