App Maintenance & Fix Bugs in WPF based Project in C#

We have an App based on WPF for the content security domain. This is currently deployed and used extensively by users. I am looking for an expert C#, SQL, ASP.Net engineer who can maintain it in terms of bug fixes/enhancements as and when arrive. Let me know if you are available and like to understand the detailed scope of work and can take it forward. Right now there are a couple of bug fixes and enhancements needs to be done in the App. This Content Security Solution is developed using WPF in C# It communicates to the server using web services and locally write data into SQL Lite file. Following big fixes/enhancements needs to be done. 1. One of the operations of App is called the upgrade package where App needs to traverse a directory structure, look for certain patterns and copy them into different directories. There is a bug (Looking for a specific pattern) in this functionality that needs to be fixed. It also needs to verify if the upgrade is for the same package by looking at certain parameters. 2. Call a web service (Web service is already available), save the details in local SLLite DB and then Enable/Disable certain controls on UI based on the info received from local DB. 3. Fix bug in not receiving certain parameters from OS to determine the unique identity 4. App not closing under certain circumstances on clicking the close button and active under tasks