I need an asp.net web store built that integrates with Sage 1000

General information for the business: Selling products online
Kind of development: New program from scratch
Description of requirements/functionality: I need to get a current asp.net webstore re-developed from scratch probably with about 50-100 products, with online user login and registration that integrates with an existing Sage 1000 set up. I also need specific product lists per user and suggested products and offers that the user can buy. Is this possible? I can provide design psds.
CMS and Admin requirements: Sage 1000 integration and user registration administration
Specific technologies required: Current build is asp.net but happy to take suggestions on a different approach.
Extra notes: How much would this be roughly and how long would it take to implement? I would also need some guidance on how to maintain the site and train the client to use the administration.