The equation to lose weight is simple, and is to take in less calories than you expend. Yes, you knew that all ready didn't you? However, very few diets encourage you to do this in a balanced way, or adress lifestyle issues. Firstly, it is not advisable to try to lose that much weight in such a short time, to achieve such weightloss you would more or less have to starve yourself, causing your metabolism to slow, and ultimately, you to regain the weight in the long run. Also it is likely that most of the weight loss would just turn out to be water.
I think it is important that you should set achievable goals, as, unless you are very short, you cannot be that overweight at 129.4 to begin with. Even at a pound a week it would only take you one third of the year to reach your goal, with plenty of time left until the Summer. So your first step should be to calculate your maintainence calories, which you can do at the Changing Shape website, or another online calculator.
Just for good measure I entered your details and your current maintenence calorie requirements are 2400. Now for a sustainable diet I would reccomend consuming about 350 calories below this.
So what should you eat?
An example meal plan:
1 Bowl Of Oats + Skimmed Milk
2 Egg Whites
1 Pint Water
2 Wholemeal pitta breads filled with homous and green salad.
+ A Fruit From Apple, Pear, Banana, Orange, e.t.c.
1 Pint Water
A carrot, + 8OZ (1/2 pint) milk
3/4 of a cup chicken breat boiled + 1/3 cup brown rice, + 1/3 cup green beans + 1/3 cup sweetcorn. 1 Pint Water
1/2 a protein bar, prefferably made with whey or cassein protein, non of those crap soy ones. 1/2 Pint Water
This would give you approximately 2100 calories.
This sort of diet would let you lose weight yet be healthy at the same time. It is just a sample, you don't have to follow it, but could adapt it along the same lines.
The reason for the high amounts of fibre in the diet, through the oats, bread, and brown rice is because fibre reduces insulin levels, and insulin is what turns charbohydrates into fat.
Exercise, it is crucial that you take regualar exercise, ideally more than 3 hours a week of moderate activity. Exersise boosts the metabolism, and therefore your bodies ability to process calories. 3 hours of resistence training as you are doing now, in full body 3x1hour splits, or 4x 45 minutes is fine.
Finally, good luck, and remember not to touch alcohol while on your diet.
Best of wishes,