According to most of the height and weight charts I've read ideal for 5'7" Female is 143, low end is 123.
To see how many calories you should be eating look at how many you burn at rest and sleep everyday according to your body. Fatsecret has it figured for you if you select Enter Exercise.
What you'll want to do with that is eat fewer calories than what you already burn and burn more through exercise.
To lose a pound you must burn at least 3500 calories, but you don't want to burn more than 2-3 pounds per week. No more than .5-1 pound when you are getting within 10 pounds of your ideal weight.
It's best, in my opinion, to burn most of your calories through exercise instead of through omission of calories in your diet.
I didn't attend the funeral, but I did send a nice letter stating my approval. -Mark Twain