Just realized...

... In episode one of Season 5, the Doctor's Sonic Screwdriver gets burned out from using too much power and falls to the ground as a useless, blackened lump of metal. In Silence in the Library, River Song has the Doctor's sonic screwdriver - the EXACT same screwdriver that the 10th Doctor has, the SAME screwdriver that gets burned up beyond fixability. Eleven gets a new one from the Tardis, a green one. So, how did River Song get a fixed AND upgraded screwdriver?