Cardio is extremely beneficial to any fitness regimen no matter what your goal may be, but what is just as equally important is strength training! Even if your goal is weight loss, not any muscle building, by incorporating strength training moves and adding muscle you are going to burn more calories even while at rest. Plus adding muscle is going to give you a leaner, more defined look. I wrote an article about this same topic not too long ago http://www.bodytransformationlab.com/weight-training-vs-cardio-for-optimal-fat-loss/
that may further the explaination of why you should be incorporating both into your fitness regimen. I'd advise adding at least 2-3 days of strength training into your program!
Hope this helps and good luck to you!