Splitting a project - GUI

[minime]

I'm trying to split a project that I have written into two separate parts.
I currently have a c++ project with a front end programmed in Win API.
The front end is encompassed in a module(named front end) and the actual workings of the program are in another part (named recovery).
Recovery calls several other modules for the workings of the program.
As programming in WinAPI is tedious and the GUI itself doesn't do any major processing (recovery does so want to keep it as pure C++ rather than Visual Studio managed code), I want to change this to a VS project and use they GUI tools, but still keep the recovery module as it is.
I was thinking I could convert the recovery and associated modules to DLL's and then link them to the GUI project, however this could cause problems when I need to debug the program and would like to be able to run the project straight from VS as I can now.
Is it possible to add a VS GUI project to my project without changing the whole code to VS managed code?
Or is there a better solution.
Sorry if any of this is unclear!
Edit: Using Visual Studio 2010

[kbw]

It sounds like a reasonable approach. If that recovery thing is made into a DLL then any interface can use it.

I don't quite understand what the difference is between the GUI you have and the proposed GUI.

[minime]

Currently, the entire GUI is written in API, which is tedious to change and update.
The new GUI uses the Visual studio forms, however as I understand it, this means it moves to managed code (slightly slower), I wanted to keep my recovery module as quick as possible and write in pure C++.
The GUI can be a lot slower and therefore can be made using managed C++.