unfortunately they do not sell those separately (at least in retail stores they do not). you MIGHT be able to get Sony to fix it, but it'd a slim chance since you've had it over a year. Most additional protection plans offered by retailers such as Target, Best Buy, or what was Circut City are only two years which this would not fall under either. Fixing this is going to be a very difficult thing to do.
My advice to you is to replace the entire thing because after paying for the part (if you can find it), you'll also have to pay for labor, and shipping and handling, which can be expensive. I suggest purchasing it from Best Buy because i know that their additional protection plan covers that, in case it happens again.