This plugin can be used to batch upgrade previous versions of Revit files to the Revit 2012 format.
Allows anyone with a digital camera to create near accurate 3D models from photographs using the web.
Here is a good guide on how to install the Google Earth Extension in AutoCAD.
There is a workflow which allows the topography from Google to be placed into Revit. You could try:
AutoCAD with Google Earth Extension – Export DWG – Import/Link into Revit
Sketchup – Save SKP – Import/Link into Revit