First recover what's left of the refrigerant. Remove cowl panels on each side of wiper assembly. Remove wiper assembly. Remove large cowl paneling under wiper assembly. Unscrew 10mm nut to remove lines to expansion valve. Unscrew two allen bolts going through expansion valve(these are very small allens, like a 3 maybe. Remove expansion valve and replace all 4 orings. Replace the reciever drier and all o rings. Check to make sure the lines going to the expansion valve are not leaking as these commonly do. I hope this helps. The job should take you a few hours.
Dustin