Yes that conditioner is quite weak, my friend used to have such a car aswell and had always those problems. But not only him, but also me. Got recently a BMW that has quite problematic conditioning, yet is good enough. But I really wanted to fix that, and trying - I did even worse and couldn't fix it myself. I went to services but they neither could solve it. I really struggled for a long time, cuz it was summer and I didn't enjoy tripping at daytime under 35celsius, geez. Anyway, thanks to mates from socool.sg it is really fixed now, huh.
Dont try to fix it yourself! It might make the problem worse, and some companies may not want to help if they see that you have tampered with it. Always call up a reliable aircon installation service company to help! Cheers