dont switch to r134, just get some artificial r12 and you can fill it up urself, but i'm not sure what exactly is wrong with ur system, your compressor might be bad or you might have a leak somewhere, and to find a leak or change a compressor it takes some knowledge and tools. since your AC system didnt work for last 2 years you need to vacuum the system first, then put some refrigerant with sealant to make sure there are not leaks, vacuum it again and put refrigerant with die, at this stage you will also be able to check if your compressor works, if the pressure in the system remains the same for a weak it means there are no leaks and ure good to go, otherwise locating and fixing the leak might be a really expensive exprerience.