They need to pretend the initial launch didn't even happen, and aim for a holiday relaunch this Christmas. Massive price-cut, strong line-up of games (should be in place if e3 rumours are anything to go by) and a decent marketing strategy for once, and I don't see why it can't be turned around.
I say this without snark or malice: I'm glad I got out when I did. Nothing wrong with the console per se, but the public reaction to it has been terrible. They were already putting the games on clearance here a month after launch, and now they are clearing out the consoles at bargain bin prices. You could pick up a Pro for less than the price of a 12GB PS3. I can't see what Nintendo can do to turn this around.