Height is mostly determined by your genetic predisposition, that is if your parents are short, then chances of you too having less height are more.
But at your age certain yoga asanas can help you to gain few more inches.
Also increase intake protiens and calcium in your diet.
You must sleep for 8 hours every day, as during sleep a hormon called growth hormon is secreted, it is very important for gaining height. Those who do not get adequate sleep tend to be shorter in height.
For weight gain increase intake of protiens and start work outs, it will build your muscles and result in weigh gain.
Please do not take any supplements that make claims of weight gain with out doctors advise, many of the supplements sold on net or other media may contain harmful anabolic steroids.