AWS launch-time in seconds

I searched endless hours for this but I was unable to find anything that could help me. As you can see, I've already wrote the code to retrieve the launch-time of a running instance and I just need to get it in a proper format so that I can use dateDiff() function to find the total instance running time in seconds (i.e. till now).

'getltimef' should be in dateDiff readable format and 'timeinsec' would be the final output (time elapsed). Starttimer() function would start a silent timer that will also keep updating the value of 'timeinsec' variable.

Could someone help me with this, please?

References:

1] PHP Parsing Amazon EC2 instance 'launchTime'

2] http://ift.tt/1JGnvE6

Function getinfo()

Set instanceid = CreateObject("MSXML2.XMLHTTP.3.0")
Set regiondata = CreateObject("MSXML2.XMLHTTP.3.0")

instanceid.Open "GET", "http://ift.tt/N6UOsk", False
instanceid.Send
regiondata.Open "GET", "http://ift.tt/1lcAxuq", False
regiondata.Send

Const getltimeFinished = 1
Const getltimeFailed = 2
getltimeCommand = "aws ec2 --region " regiondata.responseText " describe-instances " instanceid.responseText "--filter=""launch-time"""

Set getltimeShell = CreateObject("WScript.Shell")
Set getltimeShellExec = getltimeShell.Exec(getltimeCommand)

Select Case getltimeShellExec.Status

Case getltimeFinished
   launchtimedetermined = true
   getltimeOutput = getltimeShellExec.StdOut.ReadAll

Case getltimeFailed
   launchtimedetermined = false

End Select

if (launchtimedetermined) = false Then
timeinsec = 240
Else

'getltimef script'
'getltimef = maybe regexp can work here?'
'timeinsec = datediff("s", getltimef, now())'


Call starttimer()

End Function    

Thank you!