You can do it yourself, get a kit that has the fittings and retrofit label, replace the receiver/drier and the fittings. I would also change the expansion valve. Add the required amount of oil, I prefer PAG oil over Ester. Most Mopars take PAG 100. You can charge it yourself or take it to a shop, have them draw the system into a deep vacuum then charge it. Start with 80 percent charge, but you can go up to 100 percent charge of the R134A. There should be a sight glass on the receiver/drier, when the air is gone it's full.