If you've never done AC work, it will be very difficult and costly for you.
Besides opening up the dashboard and/or firewall (not sure which; I've never replaced one on an Ex), you'll be opening the sealed AC system, which means depressurizing, evacuating, and recharging the system. You'll also need to replace the dryer while the system is open.
All this requires renting a vacuum pump, acquiring a set of gauges, and knowledge of how much gas to put back in. Unless you've done it before or studied alongside someone doing it, odds are it will be much more work and trial-and-error than you bargained for.
Sorry to be a downer. It's just a complex job, no two ways about it.