Content manager and redesign por Non profit organization web

we want to update our web site. We want a new web design and a content management installation. We develop the site for our organization, de igual a igual, some years ago. May be Joomla is a solution but we are open to any system simply to install and to maintain. In the new site we want to have : User registration Different users type with different Content access Emailing by user group User forum Now or in the future we want: Simple On line accounting module Survey module Member management module The project must include also the migration of the old content to the new system. We no idea of the total cost, but we are a non for profit organization with very limited resources.