No hard code file name in program pass it at prompt

I would like to pass the program name and file to process instead of hard coding it in the program.
Program Name:Costco_ESD.vbs
example at dos prompt do Costco_ESD.vbs flatfile1

Set objFSO = CreateObject("Scripting.FileSystemObject")
' Create the regular expression object
Set objRegEx = CreateObject("VBScript.RegExp")
' Sets or returns a Boolean value that indicates if a pattern should match all occurrences in an entire search string or just the first one
' We set it to True to return a collection containing all matches
objRegEx.Global = True

' Input file
strEDI = "C:\Program Files\TIE Commerce\eVision\Coscto_ESD\single_files\Split_20110324_15265623_001.asingle"
' Output file
strOutputFile = "Outbound_001.txt"
' This is the regular expression pattern that we must find in the file. If it is not found, blnTriggerFound is left at false, and no data is output.
strTrigger = "[\r\n]PID.*ESD.*"
' This array holds each of the regular expression patterns to find in the file.
' [\r\n] matches a line feed, so, to match a string at the beginning of a line, we use this first
' .* returns multiple matches of any character, which is basically just anything after the specified text
arrDataToRetrieve = Array("[\r\n]BEG.*", "[\r\n]DTM.*", "[\r\n]N1.*ST.*", "[\r\n]N3.*", "[\r\n]N4.*", "[\r\n]PER.*", "[\r\n].*PO1.*[\r\n]PID.*ESD.*")

' Set output message to an empty string
strMessage = ""
' Set the flag for the trigger to false
blnTriggerFound = False
' Open the input file
Const intForReading = 1
Set objEDI = objFSO.OpenTextFile(strEDI, intForReading, False)
' Read all of the file into a string variable to perform the regular expression searches on
strAllText = objEDI.ReadAll
' Close the input file
objEDI.Close

' Set the regular expression pattern to look for
objRegEx.Pattern = strTrigger
' Perform the search on strAllText, returning all matches to the colMatches collection
Set colMatches = objRegEx.Execute(strAllText)
' Check in the trigger was found, based on whether the count of mathces is greater than zero
If colMatches.Count > 0 Then blnTriggerFound = True

' Enumerate through each element in the arrDataToRetrieve array, so search for each pattern
For Each strData In arrDataToRetrieve
      ' Set the pattern
      objRegEx.Pattern = strData
      ' Search strAllText for each pattern
      Set colMatches = objRegEx.Execute(strAllText)
      If colMatches.Count > 0 Then
            ' Enumerate through the returned matches
            For Each strMatch In colMatches
                  ' Trim off the carriage returns from the matches (because we used /r/n)
                  If Left(strMatch, 2) = VbCrLf Then strMatch = Mid(strMatch, 2)
                  If Right(strMatch, 2) = VbCrLf Then strMatch = Left(strMatch, Len(strMatch) - 2)
                  ' Append the match found to our output string
                  If strMessage = "" Then
                        strMessage = strMatch
                  Else
                        strMessage = strMessage & strMatch
                  End If
            Next
      End If            
Next
' Trim the carriage returns and line feeds from the final output string
If Left(strMessage, 1) = VbLf Then strMessage = Mid(strMessage, 2)
If Right(strMessage, 1) = VbCr Then strMessage = Left(strMessage, Len(strMessage) - 1)

' Check whether the trigger was found, and only if it was found, output the data to the output file
If blnTriggerFound = True Then
      ' Create the new, empty output file
      Set objOutput = objFSO.CreateTextFile(strOutputFile, True)
      ' Write the message
      objOutput.Write strMessage
      ' Close the output file
      objOutput.Close
      MsgBox "Data has been output to " & strOutputFile
Else
      'MsgBox "Not found"
End If