VB6 Astro API Development

I have a mature astrology application written entirely in Visual Basic 6 and I now need a clean, well-structured API layer so the core engine can be called from other systems—first priority is seamless integration with external database systems... (Budget: ₹12500 - ₹37500 INR, Jobs: API Development, ASP, Database Programming, JSON, RESTful, Software Development, VB.NET, Web Services)