Corporate Website with Client Login Accounts, admin and CMS

I need to create a website for my company, a simple website with additional features such as 1. Client Login/Accounts (so that clients can log in and and get updates about their projects or any other messages) 2. admin (to manage client accounts, to send updates/messages to clients' accounts, both individually and in bulk) 3. Content Management System (which will enable other admin members to log in and update articles with an option for images also) The website's going to have a cover page, where the 'login/signup' buttons are placed. There will be other stuffs on the page, like about us, services, etc, which will be added later. Right now, i need the login system and CMS setup, which i can reuse if i have to. A simple guideline/manual would be great to have along with the product. The budget i've got for this is not more than USD 100. More info when you get started. Thanks victor