Possible A/C problem?

Alright I think I need some help figuring out why my A/C isn't blowing cold. Awhile ago we recharged the system (approximately 100k) and I'm at 118k now. At 100k it would blow pretty icy cold. Before it was recharged it blew just like it does now, which is basically just being blown in your face. We put die in the system to check for possible leaks and came up with nothing. So I let it be. Now I'm at 118k and I'm down here in Georgia and it is so hot. The air being blown in my face really isn't doing much for me and I feel there is a definite problem in my system somewhere. I feel there is a possible slow leak somewhere, or maybe it could be something else. I haven't really worked on A/C systems much so I don't really know where to look and what to look for. If anyone could help me out I'd really appreciate any kind of advice.