Get a 3.5" External USB enclosure with an external access on it. Then you can get a desktop optical drive, put it in there and be done with it.
Here's an enclosure that's sort of close to what you need: http://www.amazon.co.uk/Sumvision-Apex-inch-SATA-Enclosure/dp/B004LX186C/ref=pd_sim_computers_15