Assuming it's not liquid-damaged, go to an Apple store and tell a "genius" you would like to have the machine sent to Depot for repair. Depot is a company that works closely with Apple, and has the capacity to repair most current Apple laptops for a reasonable fee. I believe the last aluminum Pro I took in ended up being about $330, and it's a comprehensive flat-rate fee which covers all necessary repairs. They also give you an Apple 60 or 90 (I don't remember which) warranty on the work they do. A Depot repair is generally a far better deal than going out and buying the logic board yourself, etc.

Sometimes "genius"es play stupid and deny Depot exists, or claim that for one reason or another a Depot repair is not possible, but I've found that if you're friendly and you specifically request a Depot repair, it's something they generally will let you do. But again, make sure there's no liquid damage, or it will come right back to you unrepaired.

Here's a question: There's a company out there, possibly Depot itself, that has a web page and that lets you go to them directly with this kind of repair...anyone know the name of it? I used to have their page bookmarked, but I've lost track.