You will need to find a protein supplement that is acceptable to your diet, probably a soy protein powder. You also need to take a multivitamin if you don't already. These two things will help a lot with body building given your current nutritional needs.
As a vegan who wants to be a bodybuilder, you absolutely need to get enough protein. You can do this via natural foods like beans, nuts, and soy products. You can also supplement with soy protein powder if you so desire.