Don't Sell Yourself Short
Brother of The Benz, The Bob
What you want to do is normal for we DIY owners.
What you must do to get your A/C back to working is so simple that you will amaze yourself.
To purge the R-134A to the atmosphere is no crime against nature.
Go to your favorite auto parts house and purchase a charging hose/can-tapper/low pressure side. In addition buy a low side pressure gauge compatable with the other hose or a complete gauge set.
You won't spend over $30.00 for all.
Three cans of R-134A and a "Hot Shot" oil charge with stop leak and a dye leak indicater.
The oil in your system will remain there if you purge the gas slowly.
It would require that the system be pumped down to a vaccum, not only to aided in the inital charging of the gas, but to dry the system of any moisture that may be present. You can charge the system without pumping it down.
The pressure gauge has a colored scale indicating when you are at the right pressure.
Don't doubt yourself, just do it.
Happy Trails beep Beep from The Spiderman in Houston!!!