[Effendi]

Coverage in the Alps cannot be perfect, so prepare to find yourself without signal sometimes. TIM should have the best coverage (expecially for 3G), probably followed by Wind (mostly GSM only, maybe some EDGE and little 3G). Vodafone is too expensive and AFAIR doesn't have such a great coverage on the Alps.

A good solution could be a prepaid card of the MVNO Nòverca (which uses TIM network).

There's a special option to call Germany at € 0.19/min (landline) or € 0.35/min (mobiles). No set-up fee, AFAIK.
There's a data option which offers you 1GB/month for € 11.00/month. Not the cheapest, but not so bad.

IMHO it's much better than a TIM Prepaid. The only con is that you have to buy it online (and they'll send it to your hotel) or go to an Intesa San Paolo bank (they are very common) and buy it there.

Wind has cheaper options for data, but for calling Germany it's € 0.20/min (60/60) plus € 0.15 set-up fee with the Call Your Country Option.