Timeturner question - comments anyone?

[Auria]

No: HPFGUIDX 135618

Does anyone know what happened to Hermione's timeturner which she had 
throughout PoA?  As far as I remember it was never explained whether 
she still has possession of it.  If she does then why have they never 
thought to use it to reverse time and save Sirius in GoF and later 
perhaps to 'save' Dumbledore??  I know that the timeturners in the MoM 
were all destroyed at the end of OotP but Hermione's one may still have 
been at Hogwarts. A possible hole in the plot me thinks!

Auria