If A1 is the cell with the information in it then the following formula should work.
This makes the assumption that
03.01.2011 is January 3rd. If it's March 1st, you need to swap the second and third terms in the
Gansi's suggestion will not work for two reasons (one and a half, depending on your location regional settings).
Because changing a cell's format from text to a number does not automatically recalculate / alter the data in the cell - you'd need to re-enter the data (e.g. by pressing F2 and then enter)
(or 1 1/2)) In UK / US date formatting, Excel would not recognize the dots as delimiters in the date. This may not be true in other regions (possibly Germany?) where this usage is more common.