MedHelp has an excellent food diary that you could/should try out. Many find that tracking the food they eat, is a huge help, because it lets you see, at a glance, how many calories you are consuming, and whether or not you might need to cut back in one area or increase in another.
Opt for low glycemic foods - those that won't spike the blood sugar, such as whole grains, veggies, etc. Stay away from anything with processed sugar, white flour, white rice, etc.
Think about yoga for a starting exercise. It's low impact and will help you tone muscle and lose weight. Exercise doesn't have to be "painful" to work.
There's really no magic diet. It's all about math: calories in versus calories out. Joining a site like Spark People or My Fitness Pal can help you stay on track, identify good and bad patterns in your diet, log fitness, and find support with others who have similar goals. Have you ever considered hula hooping? It's a really fun way to get fit, and it burns 400-600 calories/hour.