Lots of people have given advice here already but I just wanted to say that any weight you lose in this way (severely restricting your food) will all pile back on as soon as you start eating a healthy amount again, and you may well end up heavier than you started. Quick diets don't work. They're simply not sustainable!
If you want to lose weight, make small changes (reducing added sugar, choose low fat options, walk instead of taking the bus when it's reasonable) and over time these things will add up. It will take longer but you will feel better and be more likely to keep the weight off.
Exercise wise, get active 3 or 4 times a week. Don't over do it or force yourself if it's genuinely not enjoyable for you. Find things you enjoy that get your blood pumping and mix it up. Don't do the same workout over and over. Maybe go for a run one morning, do a pilates class a couple of days later and then go to the gym and work with some weights at weekend (or get some dumbbells and work out at home).
Food wise, don't go below 1200 calories as an absolute minimum. If you're active then 1500 is probably closer to where you want to be at.
A sample day of food could be:
Breakfast: bowl of porridge (40g oats, 150ml milk of your choice) with mixed berries, chopped walnuts and a tsp honey.
Lunch: Small chicken flatbread (lower calorie than 2 slices of bread) with low fat mayo, a packet of savoury snacks, a piece of fruit
Throughout the afternoon: crispbread/crackers (like Ryvita) and sticks of celery and carrot with hummus, 1/4 of a melon
Dinner: Something along the lines of roasted Mediterranean vegetables with a portion of lime and coriander cous cous and paprika spiced chicken breast strips. Or chili con carne made with lean mince and an emphasis on the chili mix rather than the rice. Two things about dinner- firstly is portion size (learn how much pasta, rice or cous cous you actually need as people often make too much and end up overeating) and secondly, bulk out your meals with loads of vegetables and low GI carbs. Carbs are not the enemy! We need them!
Dessert: a yoghurt (whatever takes your fancy like low fat greek or no added sugar) and a few squares of chocolate