Modify macro to be relative

Hi Everyone.
I have with some help from the kind people on this forum managed to make a small macro that converts a column of timestamps that is not in a format excel can recognize as date time into a excel date time format. It works a treat and I am very happy with it.

Sub Timestamp()
    '
    ' Timestamp Macro
    '
    ' Keyboard Shortcut: Ctrl+t
    '
        Range("C1").Select
        ActiveCell.FormulaR1C1 = "=LEFT(RC1,10)+(MID(RC1,12,8))"
        Range("C1").Select
        Selection.Copy
        Range("B1").Select
        Selection.End(xlDown).Offset(0, 1).Select
        Range(Selection, Selection.End(xlUp)).Select
        ActiveSheet.Paste
        Columns("C:C").Select
        Selection.NumberFormat = "d/m/yyyy h:mm"
    End Sub

http://www.excelforum.com/excel-gene...date-time.html
The next step for me now will be make the macro able to be used in different columns.
At the moment I can only use it with column A and the new date time is put in column C.
The data I import always contains 2 columns and I would like to put more than one lot of data onto a sheet.
Is it possible if each time with my mouse I highlight the top cell two right of the column where the imported timestamp is eg G3 when imported timestamps start at e3 and then run the macro from there.
Any tips much appreciated
cheers rileyp