So far your setup has been developed with focus on mechanical grip only. If you are confident that you have achieved all the mechanical grip possible then you can put some attention into the aerodynamics of the car... Specifically, reducing the drag if at all possible without sacrificing your overall lap times.

Before making any changes, run a few more laps on the setup until you feel you have reached a good benchmark lap. Return to the garage and reduce both the front and rear wings by an equal percentage. Small amounts are good to start with as you may not feel a big change, but your lap times will show if you are headed in the right direction.

Keep in mind, you only want to carry as much wing (drag) as is needed. Having more wing in place then is truly needed is only slowing you down at times you need to be at your highest speeds. Pick the one 'most-important' high speed corner, or sequence of corners, and carry only enough wing to safely and comfortably navigate through those corners. 

Continue refining your aero package until you no longer see any further gains. Once complete, revisit Steps 2 though 11 as many of these items will have changed. Gearing will certainly require a change, as may ride height, camber, tire pressures, etc.

Again, it is a never-ending development process. Once you think you are near completion, you will search out other areas that can be further refined. Take your time and enjoy the gains you find. If you do not find gains in time, you are still finding them in knowledge as things not-to-do next time. So, no matter what you do, it is either lap times gained or knowledge gained.