The anti freeze has nothing to do with your A/C. Your probably low on R134A (Freon) or out. To do this properly you need to take it to a certified A/C Tech to have it recharged.
The tech needs to pull a vacuum on the system if it's out and then properly recharge it to the correct pressure.
Also if it has some refrigerant in it. He will need to recover it before pulling the vacuum. The freon can not be vented to the atmosphere. It must be properly recovered.
