my A/C in my car is starting to blow hot air. it gradually got hotter and hotter in the past couple months. i bought a cannister to recharge it and that didnt work. one side got cold but soon stopped working and both sides are still blowing hot air.
Take it to a reliable AC shop for a proper recharging.
A/C is best fixed by an expert. Take it to one, as @Yosemite recommended.