Welcome Les! Have the A/C system tested first for leaks. Your regular garage that you use can do it. I use Bileth Services on Kraft, south of 68th st. As for the generator, I'd leave it. Works fine. If it ever needs a rebuild, I use Southwest on Chicago Drive. Guys, Les and his very nice wife, (sorry Les, I feel bad about not asking her name) are the new owners of our '62 LeSabre.
There are machines that remove the old Freon, pull a vacuum and recharge the system automatically. A proper recharge is by weight. Find someone that has R 12.