Connecting Two On-Site Installations (Open Cart and Freelance Suite)

I have installed OpenCart and FreelanceSuite on my website. The former will be used to sell packages and content sets from my company. The latter will be used to manage projects and client invoices. I want to integrate the two to use a single login so that if someone signs up for a Store account through OpenCart, it creates a new account in Freelance Suite and vice versa. I also want to make it so people who purchase a product in the store can immediately see the purchase in their client account through Freelance Suite. So, the order should be imported immediately into our project management software. Please provide a bid based on the amount of work you foresee being involved, how much time you believe it will take and what custom coding is needed. Thanks! ~Anthony