Trying to add a few extra fields under Member Groups however not managing to Save the data.

I would also like to know how I can extend EditMemberGroup.aspx into my own aspx file and location.

My code So far:

EditMemberGroup.aspx

<%@ Page Language="c#" MasterPageFile="../masterpages/umbracoPage.Master" CodeBehind="EditMemberGroupCustom.aspx.cs"
      AutoEventWireup="True" Inherits="umbraco.presentation.members.EditMemberGroup" %>

<%@ Register TagPrefix="cc1" Namespace="umbraco.uicontrols" Assembly="controls" %>
<asp:Content runat="server" ContentPlaceHolderID="body">
<input type="hidden" id="memberGroupName" runat="server" />
  <cc1:UmbracoPanel ID="Panel1" runat="server" hasMenu="true">
    <cc1:Pane ID="Pane7" Style="padding-right: 10px; padding-left: 10px; padding-bottom: 10px;
      padding-top: 10px; text-align: left" runat="server" Height="44px" Width="528px">
      <table id="Table1" width="100%">
        <tr>
          <th width="15%">
            <%=umbraco.ui.Text("name", base.getUser())%>
          </th>
          <td>
            <asp:TextBox ID="NameTxt" Width="200px" runat="server"></asp:TextBox>
          </td>
        </tr>
        <tr>
          <th width="15%">
            <%=umbraco.ui.Text("Comments", base.getUser())%>
          </th>
          <td>
            <asp:TextBox ID="NameTxt1" Width="200px" runat="server"></asp:TextBox>
          </td>
        </tr>
      </table>
    </cc1:Pane>
  </cc1:UmbracoPanel>
</asp:Content>

EditMemberGroupCustom.aspx.cs

#region Assembly umbraco, Version=1.0.6676.26629, Culture=neutral, PublicKeyToken=null
// C:\Dev\UmbracoPortal\packages\UmbracoCms.Core.7.10.3\lib\net45\umbraco.dll
#endregion

using System.Web.UI.WebControls;

namespace umbraco.presentation.members
{
    //
    // Summary:
    //     Summary description for EditMemberGroup.
    public class EditMemberGroupCustom : EditMemberGroup
    {

       protected TextBox NameTxt1;

    }
}