Here's what I would do if I were Sony:
1) DAMAGE LIMITATION: Wii is capturing the mass market. Although PS3 sales are bad, there's still some market base installed, so capitalize on it, encourage 1st-party development, release some great games and try to retain 3rd party, even without exclusivity. A bit like what Nintendo has been doing with the N64 and the Gamecube (those consoles were commercial disappointments but not complete failures). Don't drop the price of the PS3 anymore (at least until it stops loosing money out of the box).
2) GROOM CUSTOMER BASE: you do this by releasing quality games on your installed base, that is not only PS3 but also and maybe more importantly PS2. There is an amazing amount of PS2s on the planet, show the way to 3rd party developers to keep developing on it at low cost or even port Wii games (although underpowered, the PS2 can probably handle most current Wii games pretty well or with minor adjustments). For this the PS2 doesn't need to and SHOULDN'T be repackaged. Reasons why have been highlighted by other posters.
3) LOOK FORWARD TO THE FUTURE: invest in R&D (and customer surveys, this time ^^ ) to prepare for the next generation and release a truly ground-breaking PS4, capitalizing on the technical expertise gained with PS3, learning from the Wii lessons by making the product family-friendly and profitable. Reach the market only once the product is ready AND the market is ready to accept the product.
Actually maybe that's what they're doing right now 
