how to connect to query AD if the web server is not on the domain

I have the following code that works great in DEV because the DEV server is on the domain. However when I deploy the files to the web server (not on the domain), my page does not work. Do I put the connection for active directory in the web.config file, or does it get embedded into the c# (sorry, I am new to web development)?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.DirectoryServices;
using System.DirectoryServices.ActiveDirectory;
using System.Text;
using System.Collections;
using System.DirectoryServices;
using System.DirectoryServices.ActiveDirectory;


namespace MasterPageTst.SA
{
    public partial class SupportRequestSA : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            //I tried this with both lines below, I could not get either to work. The Sys Admins created a user named "MyDomain\adquery" for me
			DirectoryEntry group = new DirectoryEntry("LDAP://CN=CSR Admins,OU=ServiceAccounts,DC=MyDomain,DC=COM");
            //DirectoryEntry group = new DirectoryEntry("LDAP://CN=CSR Admins,OU=ServiceAccounts,DC=MyDomain,DC=COM", "MyDomain\adquery", "password123456");
            ArrayList ArrUsers = new ArrayList();
            object members = group.Invoke("Members", null);
            foreach (object member in (IEnumerable)members)
            {
                DirectoryEntry x = new DirectoryEntry(member);
                //Console.WriteLine(x.Name);
                ArrUsers.Add(x.Name.Substring(3));
                //ArrUsers.Add(x.Name.Replace("CN=", "")) ;
                //(Replace("CN=", "")
                //ArrUsers.Add(x.Name.Replace("CN=", ""));
            }
            DropDownList3.DataSource = ArrUsers;
            DropDownList3.DataBind();
        }


    }
}

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My goal is have the web page build a drop down list from all the users in an AD group....please help....