Yep,,there is no such thing as "spot reduction" when it comes to weight loss. Just like Dr.Vinod said, you lose the fat you put on last,,,first. So if your body just stored fat on your arms, you're going to notice a difference on your arms first. Resist the temptation to go with a fad diet. Lifestyle change is the way to go. Just as you didn't put on weight quickly, it won't come off quickly but it will come off. Go slowly. If you reduce your calorie intake too quickly, your body will assume your going into a starvation cycle and hold onto fat longer, so decreasing your calorie intake by 10% at a time, giving your body a chance to adjust to that, then reducing by 10% more, will fool your body into burning fat. Generally cardio work starts to switch from glucose burning to fat burning around 35-40 minutes into the workout. You can do it!!
You have to do cardio continously with a balanced diet. You should calculate your BMI and continue decrease in input of fat, simple carbohydrates and decrease in the calories required for your age and weight and height. The loss of weight would be proportional all throught out and also you will lose the fat which your put last. Take care!