E-Mail Notifier

Question

Requirement:
 
I have to create an automatic email notifier based on three functional conditions.this tool has to run every one hr form 0600 to 1800
1) check if there are any communication errors in the log file.
2) check if there are any unprocessed assignments
3) check the time difference between the last assignment recieved and the current date time and if the difference is more than 1 hr.
 
----if there are no errors and no unprocessed assignments and time diff is more than 1 hr an external mail has to be sent to the customers.
----if there are errors in comm logs or any unprocessed assignments left then an internal mail has to be sent.
 
 
my questions:
Based on the requirement which one is better , creating a windows service or using sql job agent and schedule it for every one hr?
 
I felt that a windows service can do it but,  we already have a email notifier stored proc which is scheduled using sql jobs.
 
i have already created a stored proc for the second and the third requirement ( checkin for hte unprocessed and calculating the time difference), but im unable to do the first one
 
the comm logs are generated by some tool called mercator, it generates a txt file (name of file is G_20100319144219.txt) .
It generates a new log file every 5 minutes.
but the servvice or the job i have to do has to run every one hr.
so i need to pick the latest log text file and scan the string for "<ExecutionSummary MapStatus="Valid" mapreturn="0" ElapsedSec="0.0119" BurstRestartCount="0"> " this line
if the file has valid then no errors or else it has errors.
 so
1) how can i pick the most recent file? and scan if for the text?
2) can i do it through a stored proc or sql ? if so i can schedule it in jobs. or
3)Can i do it throug .BAT files? i found the code for bat file which actually shows the most recent file. but i dont kno how to properly use it?
 
 
"@rem NEWESTF.BAT -
@rem Whatever.bat -
@echo off
cd C:\
setlocal enabledelayedexpansion
 
set d=00
set t=0
 
for /f "tokens=*" %%a in ('dir /b /a-d /s') do (
   set dt=%%~ta
   set dtmp=!dt:~6,4!!dt:~3,2!!dt:~0,

2!
   set ttmp=!dt:~-5,2!!dt:~-2,2!
   if !dtmp! GEQ !d! (
      if !dtmp! GTR !d! (
         set d=!dtmp!
         set t=!ttmp!
         set l=%%a
      ) else (
         if !ttmp! GTR !t! (
            set d=!dtmp!
            set t=!ttmp!
            set l=%%a
         )
      )
   )
)
 
endlocal & set lastfile=%l%
 
echo %lastfile%
 
echo.
pause
exit"
 
Thats the bat file.u can execute it and see, it shows the recent file with the path but i dont know how to use it? and this code works for the first time and i feel it has a time lag, i dont kno wat it does as i donot understand a bit of dos commands. if i modify a different file and execut it, it takes some time.i mean initially it shows the recent one but after any modifications it dosent, if i execute it after about an hr,  it again shows new one.
3) if i can know the name of the next file using the bat file above can i insert the txt file into the some table in sql and scan it by using some keyword 'LIKE' .
4) My lead wants me to do using sql jobs agent, where i can use bat files or any stored procs, When i asked him, he said try to do it in sql as thers already one process running scheduled in sql agent, he doesnt prefer windows services, he if it cannot be done then go with windows services and as far as i kno he is an expert in sql, and i dont kno even little bit in sql, so i dont want him to know that im a fresher.
 
And Yea the already existing process dosent check anything except for the time difference a sql job is scheduled to run a stored proc which checks for the time and sends a mail if the time diff is more than some configurable time