I kind of despise the word "transform" when used in the context of fitness. It just makes it sound like there is some mystical secret to changing your body or getting fit when really, there isn't. Working out under good nutrition will yield you results but genetics also play a big role in how fast or how easy it's going to be for you to get to those results.
There are a plethora of ways to diet and get fit and whichever way you go with is entirely up to you; look around and experiment. Fitness is a personal thing; do what works best for you and try not to get sucked into any money-making trends out there. If it sounds too fast and too easy to get ripped, it probably is.
Judging from your picture, you already look VERY fit; you should be proud. Strength training is important for building muscle, but try not to only focus on "arm and pec" muscles - there are muscles all over your entire body and you've already been working the most important one; your heart.
I'm not sure if I'm allowed to post links or promote other websites here, but there are a TON of excellent, 100% free resources out there that can be found easily through google or YouTube - tutorial workout videos, advice for beginners and advanced body builders and athletes, etc. If you're interested in the ones that have helped me the most, send me a private message.