Catalogue Integration

I have agreed to create ecatalogues with Yudu and need to integrate these into our website. Our website is currently hosted with oscommerce based software called openfreeway ([login to view URL]). The documentation linked provide details on the API they have. The customer should enter their userid in the shopping basket and it should then look up the user id in the customer table (mysql) and give back their address details. I would be happy to change the website software to something similar if this makes this easier. I also want the user to be able to subscribe to the catalogue on the website akin to store membership with a private members area. The software supports this but it needs configuring. I am basically open to any changes that make the future running easier. The ecatalogues will be produced monthly so I want the quote to be for setup and then monthly integration of new catalogue and other periodic maintenance. It would also be good if the products for sale on the website and their stock levels can be integrated into Amazon but that is a future project. If you could do this please state that it would be possible.