Ha ha, love it, called in sick to the boss, you being the boss!

Using my cpu my render took 1010 seconds.I could have stopped it a little earlier but was out of the room when it finished! I also changed the bucket size down to 32 from 512 for the cpu render, as GPU's like bigger numbers.

Looks like you may need to adjust the focus_distance on your camera as your pic is looking very blurred!

If you are going to experiment with DoF, I would recommend visiting bagginsbill's freebies and downloading his camtarget.obz file. It's a replacement for the crosshairs you see when using the focal_distance dial. Backup the original camtarget.obz and replace it with bb's and instead of crosshairs that can be difficult to line up your focal point if it's not centered, you get a plane to show where the focus will be.

https://sites.google.com/site/bagginsbill/Home and you'll find it in the File Cabinet section.