Although there is a way to do it (look for an example here:
http://msdn.microsoft.com/en-us/library/ms745781.aspx)
and also the inverse case, I would discourage you to use this approach.
I suggest you to start a WPF application from the ground up, of course reusing all your non-GUI classes, and suffer all the pain to learn a new technology in a single step, after a short time you will become a high skilled expert. Combining 2 technologies will distract your efforts in knowing how to glue both them.
