Simple copy/paste macro

Or if you don't know which column is the last used column:

Sub Katsdog()
    Dim lngEndCol As Long
    lngEndCol = Cells.Find("*", SearchOrder:=xlByColumns, SearchDirection:=xlPrevious).Column
    Selection.Resize(3).Copy Cells(1, lngEndCol).Offset(, 1)
End Sub

This pastes into row 1 (one), one row to the right of the last used column.