There is a host of information on exercise and nutrition on the internet, if you do your research carefully and make informed decisions, you can save time and money.
PX90 is worth a look in my opinion, so could be worth giving it a google.
I would aim for 45-60mins HITT training 3-4 times a week
Spinning, sprints, bike, circuits, treadmill, swimming.
Get a heart rate monitor, work out your zones and ensuring you stay in your fat burning zone for at least 45 minutes when you train the above.
Weight loss is 80% diet and 20% exercise, if you are serious about weight loss, work out your basic metabolic rate and ensure you are running a calorie deficit off around 300-500 calories a day. Also keep a food diary and weigh yourself regularly (I have a attached a template for you)
You burn less calories exercising than people think, don't fall into the trap of going "Oh I did 30 minutes on the bike, I can eat that pizza I want now" besides the benefits to cardio vascular health this will do nothing for your weight loss and can actually make things worse.
For example, I know guys who train everyday for hours at a time and still look like crap, because their diets are terrible and they use there time spent in the gym to legitimize eating whatever they want, you can't train away a bad diet regardless of how hard you try.
This site is good for keeping track of what you eat and what you should be eating.
Stop snacking, limit (or remove) sugars, carbs etc, you want plenty of lean meat (or protein alternatives if you are veggie) plenty of vegetables, fish, salad. Get a real picture of what is going into your body daily and make appropriate changes that can be maintained, this is the key to long term weight loss.
Tracking and having data is also motivating I find.
Aim to drink 3-5 litres of water a day, keeps you full, keeps your sharp (and on the toilet ha) and also helps with fat burning, your complexion will also look amazing :)
If you want to tone up you can lift weights a couple of times a week, free weights are best, don't need to train for more than 45 minutes. Start with compound exercise, lifts, pulls, curls, rows, toss in some press ups crunches, dips etc. 10-12 reps of each exercise start with 90 seconds rest between sets, move down to 60 seconds after a few weeks.
Form is vitally important so get a trainer to show you proper form for a selection of exercises, learn to breath properly and so on..
However, if there is an exercise you want to try, youtube it, there are great videos on there showing every exercise imaginable, often with better form and information that the majority of personal trainers in the gym.
Sleep is important aim for 8 hours a night, take time off for recovery.
Be meticulous and consistent in what you eat as well as how you train and you will see excellent results, I dropped 9kg last month, and increased lean muscle mass, most of it was fat, knocked 11% off my body fat in about 5-6 weeks.
It's not easy, but it can be done.
I also recommend a habit tracker, I find the key to making new things habitual and into long term life style changes is doing them consistently over 45 days.
If I want to change something I log it in a habit tracking app and ensure I do it for 45 days, after that it has become part of my life (much like brushing my teeth or testing my blood sugar) simple psychology but it works!
All the best, drop me a PM if you want any links or a basic work out programme to get you going.
P.S Just read my first post back, just want to say obviously you don't have to do all this at once as I imagine one would find that over whelming, but just take a long term view and make changes and incorporate things in to your life style as and when you are ready.
Also I probably should not be advising someone to be too OCD about what they eat and what their measurements are with the prevalence of eating disorders around for girls of your age either.
To conclude I would just say set your goals, eat well and for weight loss and train smart and consistently!
Hope this helps.