Integrating Actinic Ecommerce into an existing site...

I have a long term client with an existing website, they now want to add a cart and payment system to that site but it must use the Actinic e-commerce system and integrate with their Sage package to handle all stock and orders etc. I need someone who can handle the actinic setup side of it and implement it into the existing site as efficiently and quickly as possible to enable us to test and setup this new section.