Google a 'calorie counter' or there are books you can buy. Anita Bean's book Food for Fitness is really good has loads of recipies and sample diets.
Don't cut your calorie intake too drastically otherwise you basal metabolic rate drops and you go into starvation mode and start hanging onto fats etc.
1) Just consulting Anita's book now because there is a formula to work out your basal or resting metabolic rate:
31 - 60 yrs: (weight (kg) x 8.7 + 829 = BMR
Thats the amount of calories you need to just keep your body going if you did nothing.
2) Then you need to estimate the calories you need for daily activities:
Sedentary (mostl seated or standing): BMR x 1.4
Moderate (some walking during the day or active hobbies): BMR x 1.7
Very active (physically active during the day): BMR x 2.0
3) Then you need to estimate the calories you burn during exercise e.g. running for 1 hrs at 9 min/mile burns approx 750 calories. You need to work out your weekly exercises then divide by 7 to get a daily average.
Finally add the figures for 2) and 3) together and that will give you your daily intake.
Generally as a rule women's average calorie consumption is 2000 per day and I think its 2,500 for men. However these are just averages and we are all different. For instance if you are overweight you will intially need more calories just to keep your body going than a thinner person of similar age and sex.
Hope that helps or is it all as clear as mud?