Need Help! -Minecraft (1.4.5) save file seems be be corrupt, and I would like to see if i can somehow save it.

So here's the back story: I was playing MC when the power on the block went down for a couple hours. When the power came back up finally, some of the chunks never loaded, so i had some large holes in the world. I began exploring to see if there appeared to be any other errors, and soon after, the game began to lag..to the point where my save is pretty much un-playable. I would very much like to save this corrupted file, because of all the time I put into it, and I would like to know if there was anything i could do.