Sadly it was almost a freebie (no receipt) because I knew on of the mechanics and he introduced me to the AC guy who ""fixed"" my car but after my second encounter I had a nice chat with the owner of the shop and he apologized and offered to pay for the repair of the low pressure switch and changing the refrigerant which is something I would not have expected being a non receipt transaction.
In the mean time after I did some research on the forum and I fixed temporarily my AC and I discovered what was draining my battery.

I got the multi-meter and connected it in series between the - battery connector and ground wire ( thank you "compression ignite" ) and before I disconnected the antenna in the trunk I was having 3 amps of consumption, after I disconnected the antenna it dropped to 0,15 amps which I think is right, after reading some other posts. I think the fuse for the antenna was number 6.

As for my AC, I cleaned the pigtails on the AC refrigerant temp switch and I soldered back the broken pin on the low pressure switch and like magic the AC blows nice cold air again and after idling for a while with the AC turned on the passenger side fan started at full speed. Anyway I will have the car in another shop next week to get a new pressure switch and a system check.

Thank you for your help, and as for me this will be the last time I will ever visit a P.. Tune, from now on MercedesShop.com is the way to go..

I do have one question for you guys, do you think it will be ok this summer to run the AC with only one aux fan working (I am a little low on budget, I just moved from Alabama). I drove the car in heavy traffic without AC and the water did not went above 85 celsius and I know the fan clutch is working. Thank you.