How could they allow there products to be sold here, and only offer the customer the 30 day return via the reseller?
I'm obviously no expert on Canadian law here but I would be highly surprised if you are only going to get a 30 day warranty. An extended manufacturer warranty you might not get but if in law a seller has to offer a warranty, you can always take it back to them within whatever period the law states. Remember that your contract for sale of goods is with the retailer, NOT the manufacturer.
To be honest with something like a PSU it will either fail early on or after many, many years by which point it might well be obsolete anyway. The first year is the most important year to have a warranty on.