Interesting, my 03 has a leak also. I know they make some freeon that has a sealant in it. I will add some soon and let you know if it works.
It works very well, atleast for ours it worked great. ! car had a real bad leak, would lose its freon in about a week. 2 shots of the 3 n 1 sealant, coolant, and oil and it has been working great for years now.