There is, but it's expensive and you won't like it. Buying a Mac would solve your ProRes export problem. It's probably the simplest solution, and it's the best solution from several points of view.
Here's a free Windows program -- no guarantee of suitability or stability:
PC Windows ProRes encoder
If I find other software solutions, I'll edit the post.
Jeff
Here's a plug-in for After Effects, but it doesn't look simple:
ProRes 422 Conversion for After Effects (Windows) « Dubon
And another free program -- same caveats:
Pro Res Encoding on Windows 7
