I'm not a big fan of low carb diets, even though I think out of the three main macronutrients (protein, fat and carbohydrates) you can play around with carb levels the most. Therefore I'd be inclined to get onto a more balanced diet, sticking to about 50-90g fat/day, 150-200g fat/day, and the rest of your calories from carbs. I'd be sticking to whole grains and complex carbs for the most part, aiming to get most of your simple carbs (ie sugars) from milk and fruit. CrazyOldMan on these forums, if I recall correctly, says that there's a link between carbohydrate intake and metabolism; anecdotally my experience seems to concur with this, however there are more factors that warrant looking at, and a sample size of one is hardly a trend, so at this point I'll neither back nor oppose that sentiment. I will say, however, that bringing your carb intake back up will probably result in your scale weight increasing, even if you adjust all your macronutrients so that you're consuming the same amount of calories each day. This is an increase in water weight, not body fat. I don't know everything about the human body, but I hear the presence of water within it is usually a good thing. It should go without saying, but you should also be getting plenty of vegetables. The food pyramid prescribes something like 3-5 servings per day; I think 1 metric ****-tonne of boldly coloured vegetables should suffice.
Other than that, your physical activity sucks. 18min of running + "a few sets of push ups and sit ups etc" isn't a lot. Realistically, you're probably only looking at about 150-300kcal being burned that way. To put that into perspective, 1kg (2.2lb) of fat contains roughly 9,400kcal. You want to lose another 20lb, so you're looking at close to 90,000kcal worth of body fat that you'll need to use up between now and achieving that goal. if you were to get yourself into a consistent 500kcal/day deficit (which, by the sounds of things, would be better achieved at this point by increasing your energy expenditure than by consuming less food, since you're already eating only 3 small meals a day), it would take (in theory) 180 days to lose 20lb of fat. In reality, your progress probably won't be this smooth, even if you get your nutrition and physical activity right on the mark.
I'd strongly suggest making strength training more of a priority, too. As you lose weight, you lose whatever you don't need. Your body will go for fat first, but weight loss when strength training isn't prioritised still has a tendency to result in some lean body mass being lost (mostly in the form of skeletal muscle -- if you're losing other kinds of muscle, you're in real trouble). If that doesn't sound like an issue, consider the following two scenarios:
1. Someone loses 20lb, of which 5lb is muscle mass. 20 - 5 = 15, therefore at most they've lost 15lb of fat.
2. Someone loses 20lb on the scale, and at the same time gains 5lb of muscle mass. 20 - -5 = 25, therefore they've lost up to 25lb of fat.
Same difference on the scale, but one's lost almost twice as much fat as the other. Who do you think will be looking and feeling better, and in better health, by the end of that transformation?
Before work, during your break, or after work, go to the gym and do half an hour of strength training, more if you aren't running that day. You can consult with the trainers at the gym and have them put together a weekly program for you that has you training different body parts each day so that you develop your strength evenly and avoid injuries caused by overuse (eg from bench pressing 5 days a week, which would destroy your shoulders) or imbalances (eg from training your chest twice as much as your back, which would also destroy your shoulders). Here's a simple template you could use as a 5-day split:
Mon: Legs -- 3-4 exercises
Tue: Chest/triceps -- 2-3 chest, 1 triceps
Wed: Upper Back/biceps -- 2-3 upper back, 1 biceps
Thur: Legs -- 3-4 exercises
Fri: Shoulders (a balanced shoulder workout should have equal pushing and pulling, which will work a lot of the same muscles used on your chest and upper back days) -- 2 push, 2 pull