Last login Wed Aug  7, 2013 on pts/111
Last login Mon Sep 23 17:28 on pts/47 from remb02mkiwsf25
On since Feb 17 15:26:40 on pts/75
On since Jul 25, 2013 on pts/12

#!/bin/ksh
cmy=$(date +'%m%Y')
cm=${cmy%????}
cy=${cmy#??}
awk -v cm="${cm# }" -v cy="$cy" '
# Set the year associated with the month (M) and timestamp or year (TorY):
BEGIN { ML = "JanFebMarAprMayJunJulAugSepOctNovDec"
}
function setyear(M, TorY) {
        if(index(TorY, ":") == 0) return(TorY)  # We have a year; not a time.
        m = (index(ML, M) + 2) / 3              # Convert month name to number
        if(m > cm)      return(cy - 1 " " TorY) # return last year + time
        else            return(cy " " TorY)     # return this eyar + time
}
/^On since/ {
        $5 = setyear($3, $5)
}
/^Last login/ {
        $6 = setyear($4, $6)
}
{       print
}' report.txt

The below user id wre34 is not an active user from Sep 2013. his last logon Aug 7 2013
  
Directory: /export/home/wre34           Shell: /bin/ksh
Last login Wed Aug 7, 2013 on pts/111
No unread mail
No Plan.
  
The other user id ivv41 las logon was Sep 21 2013
   
Directory: /export/home/ivv41           Shell: /bin/ksh
Last login Mon Sep 23 2013 17:28 on pts/47 from remb02mkiwsf25
Mail last read Sat Sep 21 15:13:31 2013
No Plan
    
current usr id
     
Directory: /export/home/por12           Shell: /bin/ksh
On since Feb 17 2014 15:26:40 on pts/75
Mail last read Sat Feb  1 15:25:28 2014
No Plan