Hi emmah,
CalorieKing - Diet and weight loss. Calorie Counter and more is a good website for calculating calories. Also, you can google 'how many calories in [whatever food]', and you will usually get a result.
Some acronyms you will see here are BMR and TDEE. Tracy just advised you to check out what your BMR is and eat at that...I am concerned that might be too low.
BMR is 'base metabolic rate' - it's the number of calories you'd burn every day by doing *nothing*, just what your body burns by you being alive. TDEE is total daily energy expenditure, which is the total calories you burn each day, taking into account your job, any exercise, walking up and down the stairs, having a shower etc. The more active a lifestyle you lead, the higher above your BMR your TDEE will be. With calorie counting, many people recommend eating your TDEE *minus* 20%. It's not recommended to eat your BMR, but Tracy may have a good reason for recommending this to you that I'm unaware of.
These websites will help you gain a more in-depth understanding of these numbers:
http://www.minimins.com/calorie-counting/202903-answer-how-many-calories-should-i-eat.html
The Skinny Equation: BMR and TDEE Calculator
TDEE & BMR: What they are and what to do with them | MyFitnessPal.com
As long as you are eating *less* than your TDEE, you will lose weight. How much less you eat will alter the rate at which you lose it. If you eat too little, you can wreck your metabolism and cause yourself a health mischief, which is why it's certainly not recommended to eat under 1200 per day for a woman (unless you're doing an approved VLCD, which is a totally different thing altogether).
However, if you're happy at 1500 a day, go for that, don't worry about all those websites and calculations, and look forward to wearing some nice, summery dresses in a few months' time!

You don't have to drop the whole three stone you're going to lose by your holiday to feel significantly better. Even if you lose 1.5 stone you would still notice it!
Just don't then gain it back on holidays and come back and go 'Oh noes! I have to do this all again

'