string s = "..";
Regex re = new Regex(@"<a[^>]*href=(""(?<href>[^""]*)""|'(?<href>[^']*)'|(?<href>[^\s>]*))[^>]*>(?<text>.*?)</a>", RegexOptions.IgnoreCase | RegexOptions.Singleline);
Match m = re.Match(s);
if(m.Success)
{
 string link = m.Groups["href"].Value;
 string text = Regex.Replace(m.Groups["text"].Value,"<[^>]*>","");
 Console.WriteLine("link:{0}\ntext:{1}", link, text);
}