Motor Box that rotates a threaded shaft

[Legaldose]

Hi PF, I'm working on a problem for some guys and I need to add on to an existing machine. Attached is a back view of the machine (it's a drawing, sorry), there is a threaded rod that sticks out the back(white), attached to a motor at the bottom(black). There is a winged nut at the top of the shaft that cannot rotate, but can move up/down. There are cables attached to each side of the nut attaching to an emitter (pictured) and opposite that a receiver. I've looked everywhere online, but I just can't find the right motor base to go with this design, it needs to have a fair amount of torque(when the nut moves up it has to pull the emitter and receiver with it), and I would like to have it controlled via computer. Price is no object (university pays for it) however, I do not want it to be unreasonably priced.

The main part I need to find (or build) is the motor box, the rest is easy enough. So that's why I've come to you! If anybody knows of an existing part like this, please let me know. Thanks

 

[Legaldose]

I should probably mention that the motor needs to fit inside a 10.4cm x 9cm enclosure