In here, leave that layer off, for a while and get back to the animal image to define the right horn as well.
The process is the same.

So, since we're done with both of the horns, we'll need to fix their position, scalling and rotation.
For the start I'll grab the layer - "Right Horn" and rotate it for -15 degrees.

...the "Left Horn" for 30 degrees.

and then change their position to a bit higher on the image.
(however, you might wanna scale the "Left Horn" to 96% so it can be in-common with the right one).

Now, leave the horns off, and create New Layer.
Rename the new layer in - "Left Eye" and grab the Pen Tool of the Tools Palette.
Using the Pen Tool, create a Path such as this:

Right Click on the Path and chose the option - Make Selection.