Having weight-loss targets like you said is not good practice. If you're choosing a diet regime, think long-term and just eat sensibly with as much regular exercise as you can, in order to be as healthy as possible for the rest of your life, not just for a holiday.
The bike is good exercise if used properly but won't necessarily cause muscle build-up, nor will it guarantee your quickly shedding pounds and pounds. This is why you need to view your diet and exercise pattern as being for keeps, rather than for the holiday. Having short-term goals and methods just makes you panic if/when it doesn't seem to be working. Commercial diets are unnecessary - just eat a balanced diet all the time.