Using Umbraco v. 7.12

Hi, i am trying to create some functionality for a newsletter, which is supposed to be sent out once a week, which would contain everything that has been created in the last week on the site.

So every news article, event etc. I have a headline, teaser and image on every single document type, which i will use for the content in the newsletter, and ofcourse a url for the page.

My question is this.

I have created a surface controller, where i have found my root page, and from there i can look at my content. But if i go .children on the root, i would only be going down 1 level.

How do i look on my ENTIRE site, and look for everything created in the last x amount of days ?

i so far have this as far as code goes:

Other than just saying .children on each and looping through them, is there not a better way ?

  public void InitiateNewsLetter()
    {//http://localhost:50797/Umbraco/Surface/NewsLetterSurface/InitiateNewsLetter
        // this is the point that should be called...

        var content = GetContent(-14);
        if (content != null)
        {// there is content, go ahead and create the newsletter.
            var emailList = GetEmailOfMembers();
            if (emailList.Count() > 0)
            {   // there is emails present
                // create the newsletter... somehow...

            }
        }
        else
        {
            //no content to show.. well.... huh..
        }
        // meant as this is new, this is what has happened last week in case you missed it...
        // Very important, if there is no new content, it should not send out anything...!
    }
    public ActionResult GetContent(int days)
    {
        var root = Umbraco.TypedContentAtRoot().First(); // gets the main root of the site.
        var memberRoot = root.DescendantsOrSelf<MemberPage>().FirstOrDefault(); // get the memberpage "root".

        //memberRoot.Descendants

        var children = memberRoot.Children;
        var date = DateTime.Now.AddDays(days);

        var content = children.Where(x => x.CreateDate >= date); // gets content that is older than the set date.
        if (content != null)
        {
            if (content.Count() > 0)
            {
                // map the content....

                return null;
            }
            else
            {   //No content present, return null.
                return null;
            }
        }
        else
        {
            return null;
        }
        // get content from site, that has been created in the last 14 days. 
        // It will run once a week
    }
    public IEnumerable<string> GetEmailOfMembers()
    {
        var memberHelper = new UmbracoHelper(UmbracoContext.Current);
        int totalRecords;

        var members = Services.MemberService.GetAll(0, 200, out totalRecords).ToList();

        var mappedMembers = UserContainerMapper.Map<UserModel>(members, Umbraco);
        // get the email of ALL members, as an ienumerable string, and return that.
        var emailList = mappedMembers.Select(x => x.Email); // should contain all emails needed.

        return emailList;
    }
    public void SendMail()
    {
        // send the email to all members
    }