www.airsoftparts.ca is the best way to go. Dude who runs it is known as Jugglez on here, so your cousin can meet up with him and get you your RIS unit.
As for the mask, theres ArmyIssue (thats always the guys name on here) in south Mississauga/Port Credit that has almost anything you need. Whether he has that exact mask Im not sure, haven't seen it there before but its been a while since Ive been there.
www.armyissue.com should have his catalog.