The most important thing is to find the leaks (which are often obvious by a black oily residue at the location of the leak), and to ignore anyone who tells you he will convert it to r-134a for you. As you will hear many people say on this board, these cars just don't cool well with r-134a. And since the r-12 is the most inexpensive part of the a/c repair job (no matter how expensive it is in comparison to r-134a), stick with the r-12. You'll regret it if you convert.

GregS