Are the clear lens flaking and dicolored from the sun?
If they are you might save money by restoring the finish on the lens, don't fall for the cheap wipe on fixes out there go to a body shop and get a restoration kit that includes the clear coat restoration.
If you are dead set on replacing the light buckets you are in for a job. I did it in my home garage. The tools are simple but getting at the adjusters is very tricky and in tight quarters under the fender wells.
Just a note before you start take the time to mark the centers of the light for both high and low beam on a door or wall and note the distance from the wall/door marks to the headlight at the beam center you are going to need these marks to adjust to to get close the reaiming of the lights.
You can check out the exploded view drawings of the individual parts on the internet, that way you can see all the detail before you get in to it. One other note of caution you will be pushing the buckets into a curved space and snap the bucket into its bracket. be careful on how much force you apply to the bucket don't force it.