If you want to lose weight in a healthy and sustainable manner, you should set a target of about a pound a week. Of course, this number varies depending on where you were when you started and the calories you've cut. A pound a week means giving up 3,500 calories a week or 500 calories a day. If you know your energy needs, you can save any extra calories.
Stagnation is a part of any weight loss plan and should not unsettle you. With discipline and perseverance, you will soon be losing weight again. You can even lose fat and still keep your weight, because muscles are heavier than fat. So instead of weighing yourself every week, it's better to measure yourself from time to time.