Expensive... if you don't do it yourself. Best way is to call Ed. Ask for a low mileage compressor and a condenser. I'd buy a new drier as well, since they're fairly cheap and easy to replace.
Since you have a leak you can either let it bleed off the pressure (it will anyway) or have someone suck it out. Replace the parts, then have a shop vacuum it and make sure it holds. Then you can fill it yourself.
I'd recommend replacing the orifice tube, but they're a pain to get to in our cars. I'm regretting not replacing mine when I had my engine out. It would have been so easy.
_________________________
'13 Mustang 3.7V6 - MT82
'00 GP SE (L67 Swap, XP, Headers, 3.25")
'98 GTP, '01 Bonne