If you are really serious about arranging a concert, so let me give you some suggestions.
Prepare for it. Do your homework. Ask around, see if you can get any sponsors or any contact which can of help.
A good sound system is a MUST. I recall when Edward Maya came, the sound system was too bad and people were calling names to the organizers. This is legit because they had paid 6000Rs.
You dont have time for arranging it before or after Ramadan, you also have to check availability of Atif Aslam and the place where you are trying to arrange the concert.
Best ideal time is in September. You may ask why? Because in September, every university will be opened and all hostelites will be here so you dont have to be work hard to sell your tickets. The main buyers will be the university students and pindi bowys
Do check local singers. May be they will sing for free too. They will be the show starters. You can look for any university boys band, they are begging for performing.
Best of luck