You could avoid all the compiler Kung Fu and directly use windbg at runtime to detect memory leaks. See here for a little walk-through. windbg will tell you directly where the leak originates from. A very good book on this topic is Advanced Windows Debugging: Developing and Administering Reliable, Robust, and Secure Software.
I know that this is not a direct answer to your question, but I've tried the route you are trying now and dropped it pretty quickly.
I think you might want to buy Advanced Windows Debugging. There isn't anything nearly good enough on the web for you to learn this well.
You can check out the book site here:
For some other resources
From looking at the !heap documentation in the Debugging Tools for Windows help file and the heap docs on MSDN and a great excerpt from Advanced Windows Debugging, here's what I've been able to put together:
You can, however see another process's memory you do need to be in kernel mode. The API makes it easy to do from User mode. Your choice.
Kernel mode stuff and useful links I've grabbed quickly:
Try AppVerifier and GFlags together to find Page Heap corruption.
You'll likely need WinDbg as your debugger instead of Visual Studio to debug.
I also recommend this book on advanced Windows debugging for tracking down crashes such as the one you are hitting.