how i can add the "Microsoft Outlook 15.0 Object Library" to my visual studio 2012
Looks like you just need to install Outlook first.
Anyway, Microsoft does not currently recommend, and does not support, Automation of Microsoft Office applications from any unattended, non-interactive client application or component (including ASP, ASP.NET, DCOM, and NT Services), because Office may exhibit unstable behavior and/or deadlock when Office is run in this environment.
If you are building a solution that runs in a server-side context, you should try to use components that have been made safe for unattended execution. Or, you should try to find alternatives that allow at least part of the code to run client-side. If you use an Office application from a server-side solution, the application will lack many of the necessary capabilities to run successfully. Additionally, you will be taking risks with the stability of your overall solution. Read more about that in the Considerations for server-side Automation of Office article.
As a workaround you may consider using a low-level API on which Outlook is based on - Extended MAPI. Or just use any third-party wrappers around that API.
If you deal only with Exchange account you may also consider using EWS or Outlook REST API, see EWS Managed API, EWS, and web services in Exchange for more information.