The character of Dr. Zola is that of a mix of an geneticist and scientist. He is also known in the Marvel Cinematic Universe to have partnered up with the Red Skull in the creation of the Cosmic Cube or the "Tesseract" of which it's referred to in the movies, is known for forces that made practically anything possible. This tool was intended to be used against Captain America.
Later, to ensure his own survival during World War II, Zola encased his own mental being into a robot. If you happen to catch the first Captain America movie again, you can see the schematics for his machine posted in his lab.
The device was used mainly to power Dr. Zola's equipment and weapons, but it's not entirely clear what role he'll be playing this time in "Captain America: Winter Soldier".
Thoughts of Zola's evil creations such as Primus and Doughboy do come to mind and could be considered a possibly to the "Captain America" sequel which will also see the return of Scarlett Johansson, Cobie Smulders, and Samuel L. Jackson.
Hugo Weaving has no desire at returning to Captain America: Winter Soldier.
"Captain America: Winter Soldier" opens on April 4, 2014