Using the Html Agility Pack, you can leverage XPATH power - and forget about that verbose xlinq crap :-). The XPATH position() function is context sensitive. Here is a sample code:

    HtmlDocument doc = new HtmlDocument();
    doc.Load("your html file");

    // select all DIV without a CLASS attribute defined
    foreach (HtmlNode div in doc.DocumentNode.SelectNodes("//div[not(@class)]"))
    {
        Console.WriteLine("div=" + div.InnerText.Trim());
        Console.WriteLine("  header=" + div.SelectSingleNode("preceding-sibling::div[position()=1]/b").InnerText);
        Console.WriteLine("  date=" + div.SelectSingleNode("preceding-sibling::div[position()=2]/b").InnerText);
    }

That will prrint this with your sample:

div=inner hmtl 1
  header=Header 1
  date=Date 1
div=inner html 2
  header=Header 2
  date=Date 2