Question about calories while maintaining weight and cutting fat?

So I have been maintaining my weight of about 170 - 175 pounds (6'2 male, 20 yrs) for the last half a year... Hurray! actually no..

The problem is that although I reached my weight goal.. Maintenance was very hard and I think I will crash soon...

My problem is that although my weight is fine i want to cut body fat percentage (~12 right now) while building muscle. I eat ~3000 calories a day. Do cardio that shows ~900 calories burned + 1hr weight training. My diet is 40% protein 40%carbs 20%fat .. complex carbs low saturated fat all that stuff... BUT for about a month or two my weight stayed constant (maybe lost a pound or so) while not a single percentile of body fat changed.I kinda feel exausted right now and have no idea what will happen next..

Can anyone help me with this? How to cut fat and build muscle at the same time?? and the most important HOW MUCH CALORIES SHOULD I EAR???

Logic dictates that you reduce the fat % by increasing the muscle %.  The only way to gain muscle is to consume extra calories and convert the surplus energy with body-building exercises.  You'd gain weight in the process but  - assuming the absolute quantity of fat stayed very similar - the relative % of fat would drop

As gi-jane said, most people who are trying to gain muscle and lose fat to get a lower body fat, have to do it in cycles. 

You go through a "bulk" phase where you eat very well (lots of protein) and you gain weight  -- some of it being muscle.  During that time you want to really be challenging your muscles to encourage them to grow with heavy lifting.  

Then you go throu a "cut" phase where you reduce calories and continue to lift so that you maintain the muscle you have built.