A/C Service Time

I just dropped off the Supra to get the air conditioning checked out at Miramar H&A. I've been running with no air conditioning since August or September of last year. There were some days that I wished that I had air conditioning. My friend who is a Toyota mechanic told me that my freon is completely empty. So since summer is almost upon us I think it would be a good time to service it. I just hope it's something minor.