Ok if your compressor is bad you cant replace it yourself without 1. the compressor which you cant get at home depot or any other place that will sell parts to anyone without a license. you have to be certified to use the freon. 2. can you weld with an acetelyne torch? Do you have a vacuum pump? 3. do you have a gauge setup to make sure you can pull a vacuum? If you have the ability to do these things do you have access to freon and the knowledge on how to properly charge your system and a way to check your super heat and sub cooling to verify you have the charge correct?
I understand that it is expensive to have a repairman do this for you but the average handyman cant do much with an ac system except maybe change the thermostat and the air filter. Possibly the capacitor if it is obviously popped. Even a cap can be iffy if he doesnt get the right size.
Now you said it pops the breaker when it tries to start. That leads me to believe that you have a direct short to ground somewhere in your compressor. If that is the case it will never run again and you will either need to replace it or the entire condensing unit. You can't just buy these parts they are obtained through hvac distributors and they wont sell to an unlicensed individual.
Get several estimates before you have someone do it the price ranges could be significant. If you have the money replace the whole condensing unit as you will get a new warranty with it. how old is the rest of the system? if it is 20 years old i would recommend replacing the entire system if at all possible. if you ust replace the condensing unit and your indoor coil goes bad in say a year that money is wasted considering they dont make r-22 (which i am assuming is the refrigerant you have.) coils any more. so replace the condenser and the coil goes out means replacing the condensing unit again. Double whammy!
There you go advice from someone who works in this business every day. Not some handyman that thinks because they know a capacitor starts stuff in the there they are an ac tech.