If you have your design finished in Autocad 3D, it would be quite easy to simply import into Rhino, apply the needed textures, use some very high resolution and high poligon count trees, to create the mood, add a massing to construct the background shadows, and finish the job on Photoshop.
You can look into my portfolio here for some examples of my render skills, I'm an expert modeler in Archicad/Rhino/SketchUp/Blender and would use a mix of those on your project aiming for the final product. We would need to discuss how many viewports you want finished, because for your budget, I am budgeting making two output views, not so much for the machine time of rendering, but the Pre and Post Production work ( making changes to model, adding environment, finishing the job on Photoshop ).
Thank you for looking into my proposal, will be waiting for your contact if interested,
Jessica