c++ to c# conversion

We have a small VC2008 project that was written for us that consists of a single C++ dll and a simple C++ utility that calls the dll. The utility program is tiny. It allows us to upload firmware and configure a hardware device. For someone with the right skills and who can work on their own initiative, I would estimate this project to be only a few hours work. We would like a programmer to produce a new project in VS 2015, convert the C++ application that calls the dll to C#. This application is very simple and has three similar functions: select a file/encryption key, validate the file and upload via a COM port. The application should be able to use the provided DLL binary without modifications (because the dll has already been tested and validated). We don't need the dll source files to be converted, but bidders who can provide us with a combined project so that we can compile the dll alongside the c# utility would be a bonus as our C++ and VC configuration skills are limited. Compliable C++ project sources for the dll and the utility will be provided. Deliverables will be the VS2015 C# project that we can compile and run against the dll binary here.