With the new Lightroom 4 you can selectively fix the white balance using the Local Adjustments (Graduated Filters or Brushes).
First, choice your main white balance based on the strongest light source (in this case the sunlight from the window) then select the temperature compensation and add the graduated filter or the brush. If one pass is not enough you can add multiple layers.
Also a bit of desaturation and + exposure compensation can help.
You can start with the graduated filter and then add local brushes for the smaller areas.
It's useful in situations with mixed light sources like sun from a window and tugsten lights.
Or if you use a flash (without CTO gel) and mix it with indoor ambient lights.