recharging A/C?

Have you charged one before? Is it R12 or has it been converted to R134A? You'll need a set of specialty gauges to measure suction and discharge pressures, and you'll need to pull a vacuum (vacuum pump) on the system before you charge it. If you've not done one before, you ought to get someone who's familiar with refrigeration systems to help you the first time. And if it's R12, you'll have a hard time even buying the refrigerant since they 'controlled' it - you'll likely have to take it somewhere. Also, the R12 is expensive.

You're gonna have to get some assistance - it requires specialty tools and expertise. You have to pull a vacuum on the system to get rid of all moisture and air before you introduce the freon. If you've not done it before and don't have the equipment, you won't get much of anywhere on it. You can't simply add cans of freon. Is it R12 or R134A? Most places won't even rent vacuum pumps and gauges anymore since they regulated the R12. And if you have to take it somewhere, it's gonna cost. The R12 is expensive anyway. Good luck with it.