i had this feeling about a month ago, took it to the garage i always go to and had it recheaged......iirc there should of been 525grammes of gas and there was abround 300grammes, so in my case £40 well spent
o and my car isnt 2 years old yet, alot of ppl make the mistake of not running it at all and then when it warms a bit put it on and not be cold enough, apparantly if you dont use it the gas evaporates quicker than if you were using it not sure on that though.
if there is a kwik fit near to you that may be your best bet as they say if they cant your air con colder you dont pay, cant get much fairer than that.