lumina 93 a/c

I have a Chevy Lumina '93 and small problem with a/c.
I tought so I need to charge a/c system when it slowly stoped cooling the air - it is still cooling but very litle. I bought charging set and found so I may have R12 in the system when set I bought was R134a and there is not recomended to mix R12 with R134a. Here is first question - haw to check what I really have in the system?
Becouse the set I bought was with gauge I decided to check a/c system pressure, just to see if gass low pressure is the reason for not cooling. I found so pressure is ok, so there is no need for refilling! When I was checking the pressure I found also so, after few minutes of a/c running, low pressure pipe is just little bit colder than high pressure pipe and there was no condensation on the pipe, even very hot, humid day. Also, I don't know if it is related but when my wife was dirving once, year or two ago, with a/c on, she sudendly felt very strange odor from the system, something like burned wire insulation or melted plastic she turned a/c off and when she stoped the car she found so battery is dead. We replaced battery and car is still driving but we noticed so from this incident a/c is not working like before.
Can somone point me in wright direction?

there should be an A/C service label under the hood, either on the accumulator (the silver can between the compressor and the firewall, or on the radiator hold down bracket at the front of the car. If there is no label present, check the service valves on the hoses. If it is an R-12 sysem, the fittings will have external threads for the filling hose and guages to attach to (they screw on). If it was originally R-134, or has been converted over, the fittings will be quick connects, where the guages and filler hose have spring loaded connectors (similar to air compressor fittings that snap on)

there should be an A/C service label under the hood, either on the accumulator (the silver can between the compressor and the firewall, or on the radiator hold down bracket at the front of the car. If there is no label present, check the service valves on the hoses. If it is an R-12 sysem, the fittings will have external threads for the filling hose and guages to attach to (they screw on). If it was originally R-134, or has been converted over, the fittings will be quick connects, where the guages and filler hose have spring loaded connectors (similar to air compressor fittings that snap on)


Thanks Richtazz!