I doubt you'd ever get an apology from the guy who did this, as he's already sold the publication. If the publication continues to appear, you might ask the new publisher to print not an apology but a Correction, so to speak, regarding the "mistake." If it's that important to you, you might get that: An explanation to readers of the issue in which the correction appears that you were not the editor of issues X and X2, or whatever issues they were.
I personally wouldn't worry about it, unless you think those published issues of the newsletter were poorly done, and you want your name disassociated with them?
Just some thoughts...
Author: "10 Golden Rules of Freelance Writing and How I Broke Them (How to Break the Rules and Make It as a Magazine Writer)" [Shameless Plug!], now available at Booklocker.com: http://www.booklocker.com/books/1368.html