2008 Acura RDX

My wife complained that the A/C took a while to get cool.So I checked it and she was right. I thought it may need to be charged so I added refrigerant to the system about 12 oz.and 3 oz of pag oil. Then I noticed that the engine would run real rough and almost choke out every time the compressor would kick on. also the compressor would kick on and off very frequently.I then took it for a ride and with the ac on med fan it was cool but not totally cold.I then place the fan on high and it started to get warmer. I don’t know whats going on for the engine is running rough and cutting out when ever I turn on the A/C. Please can you help!