Downloading call log and importing csv in Excel, the dates are in a unusable text format. How can I change this in a date format ?

When I download the call log and import the csv file in Excel, I need the dates to be in a useful format - the way it is setup now, the dates are in text format and I can't do anything useful with this data. Also, the download feature does not allow any customization. I called tech support, but were unable to direct me. Is there a way to setup the log or download the data in order to attain this goal ?