I'd lose the eggplant from a stirfry entirely. Wrong sort of vegetable. Definitely add the cabbage, finely chopped. And julienned carrots, as well as the nuts, are a good addition as Jeff said. Broccoli is good too.
In addition to everything that was suggested, you may find that the hotdog flavour was actually killing the flavour of the rest of the dish with its sausage spiciness. They can be overpowering, making the other ingredients seem bland.
Too many restaurants, not enough time...