you need to do 200 minutes of cardio a week. Remember fat does not turn into muscle, so you need to lose your fat while putting on muscle. The 45 minute thing is not true, but don't over 60 minutes at a time.
Do 5-10 minutes of cardio to warm up, then do your weight training. Do 30 to 60 minutes more of cardio, then go home.
The best time to eat is just after your workout within an hour when your metabolism is raging. For your muscles, incorporate some isolated soy protein or whey protein. Whey is more potent but the soy tastes better!
Don't look at your scale as the be all and end all, but get a measuring tape to check your progress, and that will show more tangible results.
Good luck and stick at it.