If I were tackling this then I would use my trusty ole do some contours and get the relief in then deal with the height map. This post shows it best at #9 and #10.
http://www.cartographersguild.com/showthread.php?t=1273
Since you have the base contour done in the first post and now you have the color texture map to lay on top I think that your about 80% there if you wanted to go down this road.
If you need something to display it in 3D then I can give you this free. You just save two bitmaps of the same size, a 'color.bmp' and a 'height.bmp' in the same directory as the app and run it. You might find that this will be able to put your terraformer bump map and color map together too. If you have any trouble then post the height map and ill show you.