Website with Customer Login and Project Management Capability

I am starting an engineering consulting and design business and I need a website that allows the company to easily collect and manage costumers and projects. Each project has a submittal process, quoting process process, quote acceptance, project tracking process/project design completion (design completed separately via AutoCAD), design dissemination process, and customer invoice process. I would like the front end of the website to allow costumers to view company information, submit design requests and project documents, and receive confirmation e-mails and status updates on the progress of their requests. I need the "back end" of the website to allow me to log on, view and manage projects arranged by customers, manage quotes, download project documents, upload completed designs, and invoice customers.