Jawaduddin,
For f2d files, under the Data heading in Excel you will find an Icon for Text to Columns which will allow you to convert that one column into the 2 that are needed.
f3d files are a bit more complicated as they are a single column and need to be a 2D array based on the dimensions of your design. Usually I use the ReShape function in Matlab. You could build one yourself in Excel using their VBA scripting language which can be accessed using Alt-F11.
Scott