I got my code to work.
I added the reference Telerik.Windows.Controls. and then used the below function
.ExportToImage(LayoutRoot, fs, new Telerik.Windows.Media.Imaging.PngBitmapEncoder());
It works great and saves the image. But now the problem is once the image is saved the control just freezes up. The buttons and slider I have on the control is not clickable anymore. It just doesn't respond to any mouse click event. Any fix?