// функцию RegExp сам напишешь 
function RegExp(const Pattern, SMatch: string): string;

function ExtractDate(const Text: string): TDateTime;
var
  Pattern: string;
  s, d, m, y: string;
  YY, MM, DD: word;
  k: integer;
const
  MonthNames: string = 'jan feb mar apr may jun jul aug sep oct nov dec';
begin
  result := 0;
  Pattern := '(\d{4}\s[A-Za-z]{3,8}\s\d{1,2}|\d{1,2}\s[A-Za-z]{3,8}\s\d{4}|\d{4}[-\.\/]\d{1,2}[-\.\/]\d{1,2}|\d{1,2}[-\.\/]\d{1,2}[-\.\/]\d{4})';
  s := RegExp(Pattern, Text);
  if s <> '' then
  begin
    // extract year
    y := RegExp('(\d{4})', s);
    if y <> '' then
      YY := StrToInt(y)
    else
      exit;

    Pattern := '([a-zA-Z]+)';
    m := RegExp(Pattern, s);
    if m <> '' then
    begin
      // month as a word
      MM := pos(lowercase(copy(m, 1, 3)), MonthNames);
      if MM = 0 then
        exit;
      MM := (MM - 1) div 4 + 1;
      s := RegExp('(?<!\d)(\d{1,2})(?!\d)', s);
      if s = '' then
        exit;
      DD := StrToInt(s);
    end
    else
    begin
      // only numbers

      // get date and month
      s := RegExp('(?<!\d)(\d{1,2})(?!\d)', s);
      if s = '' then
        exit;
      k := pos(#13#10, s);
      if k = 0 then
        exit;

      D := copy(s, 1, k - 1);
      M := copy(s, k + 2, 255);

      dd := StrToInt(D);
      mm := StrToInt(M);
      // check if the date is in a sort of range
      if (not (dd in [1..12])) and (not(mm in [1..12]))   then
        exit;

      // try to guess by number what is what
      if dd > 12 then
      begin
        // this is a date
      end
      else
      if mm > 12 then
      begin
        // this is not a month

        // exchange day and month
        k := DD;
        DD := MM;
        MM := k;

      end
      else
      begin
        // check position of a year (first or last)
        if pos(y, s) > 4 then
        begin
          // year is in the end

          if Length(D) = 1 then
          begin
            // probably this is an american way of coding date
            // exchange day and month
            k := DD;
            DD := MM;
            MM := k;
          end;

        end
        else
        begin
          // year is in the beginning

          // exchange day and month
          k := DD;
          DD := MM;
          MM := k;
        end;
      end;
    end;
    if (DD in [1..31]) and (MM in [1..12]) then
    begin
      if not TryEncodeDate(YY, MM, DD, result) then
        result := 0;
    end;
  end;
end;