SQL & PL/SQL

Hello! I am trying to create a pl/sql procedure that lets me send an email and include an existing file to a email address. So far, I found information on how to send a file and create an attachment with information I put in the procedure. This is NOT what I'm trying to do. I'm trying to send an email and include an attachment for a file that already exists. I need the pre-existing file to be sent to the email recipient.

This is how far I've gotten, but this only allows me to CREATE an attachment with the information I put in it from the procedure. I got it from the following site:
http://www.orafaq.com/wiki/Send_mail_from_PL/SQL

DECLARE
   v_From       VARCHAR2(80) := 'cchang@mycompany.com';
   v_Recipient  VARCHAR2(80) := 'cchang@mycompany.com';
   v_Subject    VARCHAR2(80) := 'Weekly Invoice Report';
   v_Mail_Host  VARCHAR2(30) := 'mail.mycompany.com';
   v_Mail_Conn  utl_smtp.Connection;
   crlf         VARCHAR2(2)  := chr(13)||chr(10);
BEGIN
  v_Mail_Conn := utl_smtp.Open_Connection(v_Mail_Host, 25);

  utl_smtp.Helo(v_Mail_Conn, v_Mail_Host);

  utl_smtp.Mail(v_Mail_Conn, v_From);

  utl_smtp.Rcpt(v_Mail_Conn, v_Recipient);

  utl_smtp.Data(v_Mail_Conn,
    'Date: '   || to_char(sysdate, 'Dy, DD Mon YYYY hh24:mi:ss') || crlf ||
    'From: '   || v_From || crlf ||
    'Subject: '|| v_Subject || crlf ||
    'To: '     || v_Recipient || crlf ||

    'MIME-Version: 1.0'|| crlf ||	-- Use MIME mail standard
    'Content-Type: multipart/mixed;'|| crlf ||
    ' boundary="-----SECBOUND"'|| crlf ||
    crlf ||

    '-------SECBOUND'|| crlf ||
    'Content-Type: text/plain;'|| crlf ||
    'Content-Transfer_Encoding: 7bit'|| crlf ||
    crlf ||
    'This is a test'|| crlf ||	-- Message body
    'of the email attachment'|| crlf ||
    crlf ||

    '-------SECBOUND'|| crlf ||
    'Content-Type: text/plain;'|| crlf ||
    ' name="ap_inv_supplier_cc10.txt"'|| crlf ||
    'Content-Transfer_Encoding: 8bit'|| crlf ||
    'Content-Disposition: attachment;'|| crlf ||
    ' filename="ap_inv_supplier_cc10.txt"'|| crlf ||
    crlf ||
    'TXT,file,attachment'|| crlf ||	-- Content of attachment  (THIS IS MY PROBLEM!  I NEED TO BE ABLE TO ATTACH AN EXISTING FILE, NOT CREATE A NEW ONE)
    crlf ||

    '-------SECBOUND--'			-- End MIME mail
  );

  utl_smtp.Quit(v_mail_conn);
EXCEPTION
  WHEN utl_smtp.Transient_Error OR utl_smtp.Permanent_Error then
    raise_application_error(-20000, 'Unable to send mail: '||sqlerrm);
END;
/