Lasch told you that it isn't a good idea to overclock your notebook.
Look, if AMD Overdrive is telling you that it isn't possible to overclock it more than 2.3 GHz, don't try to! Your warranty is away since the day you overclocked your notebook.
Anyway, e.g. the fan of your notebook can't accomplish with the requirements you need to overclock your cpu that way.
Either you have to buy a new pc or you have to life with the actual speed.
By the way: why are you writting in english while your notebook is appointed in german?