Hello,
Go To Report Parameters, add a new parameter,
Select From query radio button bwlow available values, Select the Dataset which you get the result,
In the Vlaue field select 'Col1'
In the Label Field select 'Col3'
Check the Internal CheckBox.
In the Default Values Section , Give Parameters!Parameter1.Value.
In the Column Header where you required the name give as Parameters!Parameter2.Label
Hope this helps