I am 26 year old male weighing 72.5 kg and height 169cm, I have started working out(Mostly of weight training and bit of cardio) since a month and have reduced from 74.5kg. There is improvement in muscle definition, reduction is tummy a bit. But I am not satisfied with the results. My diet does not contain much protein though i consume 4 egg whites almost daily. Have I made a good progress or should I include whey protein supplement in my diet or should I wait for a few more months of workout and then consider a protein supplement.? I have worked out before as well, but was never consistent.Now I have been consistent since a month.My goal is to reduce weight and to get a good muscle definition
You lost about 0.5kg (1lb) per week, which is generally recommended for slower diets. The benefits of dieting slowly are that there's virtually no muscle loss (you really only lose fat) and better carryover of good habits to the time after the diet. Also, it's easier to stay sane and keep going, as you're probably not starving throughout the day.
So seeing how you're not really that much overweight I wouldn't recommend losing weight any faster, as that's when detrimental effects set in. You'd begin to lose muscle along with fat, performance drops, comes to a standstill or at least progresses slower. Also, a faster diet is not as sustainable and won't have that much carryover of good habits for after the diet, as faster diets don't work with good habits normally (think 'starving').
You say you're not eating much protein, which could become a problem. Protein is very important to build and maintain muscle mass. No matter if you want to get better at your workouts or just not get worse while losing more weight, you will need sufficient protein. Opinions on what is 'sufficient' differ greatly and depend on what kind of activity you're doing, so it's a bit hard to say right now. If your were weightlifting, I'd recommend 2g/kg (1g/lb) per day. If you're 'only' doing cardio you might get away with less.
Regarding protein supplements: Seeing how you seem to have problems getting enough protein in, this could be worth a try. Generally, you should be able to get everything you need from whole foods, though. Should you for some reason not be able to meet your protein goals, a supplement can help. Keep in mind that it still has calories, however (~120kcal for 30g whey), which you'd have to compensate by either eating less or working out more.