There are no pills that you can take that will help you "increase your metabolism and burn fat." Caffeine is a good substance to utilize if you are looking for some assistance. It will help increase fatty acid mobilization and you'll be able to prolong your workouts thus creating a higher caloric deficit.
Are you really serious about doing this? We are talking about hard work. Putting down your little debbies, getting off your butt and not only going on a diet but EXERCISING!!! Even if you lose the weight it will come right back if you do not have the desire and motivation to not only look cute but to be healthy. it is going to take alot of inner strength I can assure you of that.
1.) eat 4-5 small meals a day
2.) drink lots of water
3.)exercise every day
4.) do not eat 4-6 hours before you sleep.
Good luck. I mean it. You may be saving your life. I saved mine.