Wiring Ceiling Fan - reuse switch that controls outlet

I'm planning on installing a new ceiling fan and was hoping to have a few questions answered before I dive into things. First some context:

The existing wall switch controls half of the outlet on the other side of the room. I'd like to convert this outlet to be always hot and use a dual switch for the fan something like this:

http://ift.tt/1FZRGbl

I opened up the outlet and this is what it looks like (I forgot to take a picture of the inside of the box, I can do that if it helps):

http://ift.tt/1FZRGbn

And this is what the switch looks like:

http://ift.tt/1Ey5G4J
http://ift.tt/1FZRGbr

I crawled in the attic and it looks like the 12/3 romex from the switch to the outlet runs through there.

In order to set this up right, can I cut that romex line in the attic and attach it to a box for the ceiling fan? And then pull the excess line that is attached to the outlet and discard it?

In order to convert the outlet to be always hot, do I need to buy a new one? I'm assuming there isn't a way to replace the tab?

Attached Images

 

Wiring Ceiling Fan - reuse switch that controls outlet