Custom Date Format To Be Retained In .csv Also

i have the required date as part of a string, which i need to pull out and then format it as "yyyy-mm-dd hh:mm:ss" and put it in another file which will be saved as .csv

Here is the code i am trying to modify without much success so far

Sub dateFormat()

Dim dtMydate As Date
Dim sMydate As String
Dim strWhen As String

strWhen = "As on 13-MAR-2007 14:45:59 Hours IST" ' the starting string
'strWhen = Cells. Find("As on")

'take out the date portion from strWhen
strWhen = Mid(strWhen, InStr(strWhen, "-") - 2, (InStr(strWhen, "Hours") - 1) - (InStr(strWhen, "-") - 2))

dtMydate = CDate(strWhen)
Debug.Print dtMydate 'returned value is 13/03/2007 2:45:59 PM

dtMydate = Format(dtMydate, "yyyy-mm-dd hh:mm:ss")
Debug.Print dtMydate 'returned value is again 13/03/2007 2:45:59 PM...