Bokeh refers to the quality of the blur and not the depth of field. Great bokeh is achieved by high quality lenses with nice rounded aperture blades, typically 9 or more.
Now to get a nice depth of field you can still do this will and slightly smaller aperture. F4 is a good place to start. Most lenses are sharpest at f4 as well. Then maybe change it to f2.8 or maybe f2. But your focus here is not bad. I would say the posing could use a lot of work. Im not a big fan of the over the shoulder pose. Its awkward and unnatural and if the neck twists to far you start getting wrinkles in the neck. Do you know of a single woman that wants to add more wrinkles to any part of their body? No, I didnt think so.
First thing to try is have the subject turn more towards you but still be at an angle. Face pointed towards the open side of the photo (the opposite of what you have above). Then get a front facing view or maybe a 2/3 view.
I refer lots of people to this....
http://www.thephotoforum.com/forum/articles-interest/268210-guide-classic-portraiture.html
Tutorial is simple and highly effective basics.