Any shop/mechanic really should be able to help you, however I would strongly suggest getting someone involved who understands the import process. Get whomever you plan to work with involved early on in the process to help smooth the transition.
What kind of airplane are we talking about and what kind of modifications does it have?
Since it is a Mooney and was manufactured in the US, you shouldn't need an export CoA. Be very careful to insure that the airplane is truly in a configuration that is legal and acceptable in the US. Even if all the mods are STCd, I've seen some cases where the Canadians didn't have proper authorization from the STC holder to install the equipment but they did anyway and apparently it was acceptable up there. Make sure you know what you're getting and make sure you know how easy or hard the import will be prior to getting in the middle of it and having the airplane tied up for months while all the paperwork gets sorted out.
I assume you've located a DAR to work with? That would be where I'd probably start.