Fundamental Concept:

The aircon is producing cold air, but it is not strong enough to reach you. The filters are very dirty, thus inhibiting proper 
air flow.

Solution:

You can rinse the plastic filters using the shower spray, smack it against a wall to shack off the water droplets. You can put it back, it need not be 100% dry. Do not scrub the filters too hard as it may tear it. Do not use thinner, spirit or kerosene to clean it.

Now that the filters are clean, does it improve the performance?

Yes: Congratulations!
No: Click Here