You could also go to Dashboards and create a new portlet there or create the portlet first.
The portlet could be based on the task object
Then you would have all the attributes of the task objects available.
The other option is to create a query based portlet then you would have more options for the data if that is not just task data.
This is assuming that you have the rights needed (not quite sure which rights are needed)
Export to Excel would finally allow to do the actual export