Using the latest image showing Curiosity's position from today's teleconference and 2D interpolation I was able to get a slightly better position. The points marked in red below supplied the connection between the image pixel points and Google Mars coordinates.
The new coordinates are -4.589468° N, 137.441616° E. At the teleconference it was asked if the rover could cross an apparent land bridge to reach Mt Sharp but Curiosity appears to be in a bit of a hollow and one probably cannot see some of the dunes. Also the area to the right of Curiosity appears to be a bit of a rise and may block a view of the object to the east which was used to find the position. Curiosity may be able to see more if she moves to higher ground.