Where might I be leaking coolant?

About a month ago I took my car to PepBoys because I had a steady drip of antifreeze just in front of the front passenger tire roughly between the tire and radiator. I had actually gone to Jiffy Lube for an oil change and they saw the leak and told me I needed to get this taken care of asap because I wouldn't get very far. The next day, PepBoys told me that I needed a new coolant reservoir. They removed it and brought it out to me and said it was leaking near the little spout where a small black hose connects to it. I really couldn't see anything! I had no choice but to let them put in a new reservoir and I was shocked this was a $350 job. To get the reservoir out, they had to evacuate my A/C system and I left there without A/C. They said I only had 2 oz of refrigerant. I know that wasn't true because I had great A/C and actually used it on my way there! After I left, about a mile down the road the "low refrigerant" light came on and the compressor shut off. I went back and they told me I needed a new evaporator because they could hear a slight hissing sound behind the dash where the evaporator is when they tried to put some refrigerant in the car. They said that this was a 10 hour job that they don't do. It all seemed very shady to me. I wasn't happy but my antifreeze leak problem seemed to be solved until about a week later, my dash displayed "check coolant level". I needed to add about 3/4 gallon of antifreeze. I wasn't sure if it was still leaking or if PepBoys just didn't top my fluid. So another week went by and the same thing happened. Back to PepBoys I went and after pressure testing the car all they could come up with was the coolant reservoir cap wasn't holding pressure and they put on a new one free of charge. Now I was pissed because I left thinking did I really need the new reservoir! Today, a week later, the check coolant level light came on again and I had to add another 3/4 a gallon of antifreeze. I also notice a slight antifreeze smell when I get out of my car. I don't need A/C now but I don't have heat or defrost either because the compressor turns off. Do you have any idea where my leak may be or what they should check next? Do you think I should go somewhere else and deal with PepBoys later when I find the real problem and get it fixed? Thanks.