How to encourage growth in adolescence

Hi,
I'm 17 and I haven't grown height-wise at all in the last 2 years. Now I'm starting to think that I probably will stay roughly this height for the rest of my life.
I'm not particularly short as such, but that said I certainly wouldn't mind being an inch or two taller, and it strikes me that now is the time to make any changes because it's not long until I'm done growing. My dad is fairly tall (quite a few inches above me), and I suspect that probably the main reason I haven't lived up to my genetic potential is my vegetarian diet:
  (a) Leading to a lack of protein
  (b) Leading to a lack of zinc, and so testosterone.

What can I do over the next year or two to try and encourage a growth spurt before I'm an adult? Would protein tablets, for example, likely have any impact or are they mostly just a marketing trick? Are there any other dietary requirements I should be particularly aware of? And can anything in my lifestyle make a difference to my height?

Thanks,
Luke