Yes, you must find and fix the leak.
The good news is you may can FIX it from the outside depending on where the leak is.
You are allowed by the rules to put a few ounces of some refrigerant (check the epa rules) for the purpose of leak detecting. Borrow one of the leak detectors that will react to that refrigerant... then consider cleaning that area and using JBWeld to hold a brass patch on it.. the brass should not touch the metal on the condenser.. it is just a top layer for the epoxy. Follow the rules on the epoxy. Do not rush the situation.
Then recheck for leaks. Use the slow Epoxy if you have a choice.. usually much stronger... once in place do not touch it. Keep it above 70 degrees with a light if necessary. The brass does not have to be thick... 10 thou shimstock is just fine.
Hollar if you have any questions.