Clever to wait with the fatburners until you have a strong foundation in place.
For your meal at work, try this: 2 Tblsp natural peanut butter and 50g Quality Whey protein (chocolate works best). That yields 40g Pure protein, 4g Carbs, and 18g Fats. 400 calories in 2 mins. Keep your whey protein, peanut butter and a shaker in your office drawer. The fats also help to keep you satisfied for longer which is very useful at work.
Start your diet at 2400 cals, and adjust every week depending on your fat loss results and how hungry you feel during the day.
Just do your pre workout when you wake and eat a HUGE meal right after training. No fats in this meal as fats slow down the absorption of nutrients which is the opposite of what you want post workout.