Head over to the diet section and post a thread explaining your short term and long term goals then go over to the bodybuilding section and ask RADAR, ceo or one of the many other knowledgeable guys to help you putting a routine together.
You have "new muscle" if you want to add 20lbs by the end of the year you can easily do it without hurting with your body. Your body is producing everything it needs right now - chemicals will only halt your natural production.
I also suggest starting a log on here so people can follow along and help you when it's needed. This is a great community for people looking to be the best they can while being smart about it.
Good Luck!