However, as someone who has been caught out many times when buying items only to find it's replaced quickly by a later model I don't worry too much about it, as I tend to think that if I kept waiting for the next model I would end up never buying anything..lol I have had several months use out of my iPad3, and like many other owners I expected a replacement perhaps around next March... but technology moves quickly these days, though in your case I can well understand your feelings having just bought a week ago.
As a result of bad experiences in the past when trying to return items to certain stores in the UK, when ordering something now, especially if it's a pricey item, I will sometimes pay a little extra if necessary and order from somewhere where I know they have an easy no quible return policy, such as the likes of Amazon or similar.
TBH I still regard my iPad 3 64/4G as being a fairly new purchase, and certainly won't be upgrading it anytime soon, and would likely skip the next model anyway.
In the UK we have something called the 'Distance Selling Act' which gives customers 7days from the date of receipt of the item to return something as long as the condition is as received, but this only applies to items ordered online not from the store direct, though many stores do have some sort of return policy. ( some more lax than others)