How should one prep a legacy system for an observable dashboard (design patterns and libraries available)?

I have a system with a lot of CRUD forms (Win-forms; C#; SQL Server), There are plenty of entry points for data, there are calculations done via daemon services and automated data entry via XML as well. The entity relationships are also not perfect ( some foreign keys are defined in business logic rather than represented as actual foreign keys). This was developed a while back so it relies on ADO.NET for the persistence layer (No EF). The code structure does separate DB Layer, BUS layer and UI layer to some extent. Now there is a need to be able to monitor some of the data entered ( and calculated) as a summary, trend, absolute value on the dashboard, so as to any changes in the database or calculated results must update the dash board. What are my options?