There is a compressor that is available, it is not cheap and with the cost on instillation it may be less expensive to replace the unit. There is info on replacement compressors in these old units on the forum, you will just have to search. You might check and make sure the starting capacitor is OK, it may not be the compressor.
This is a link to TomW's web site and the work he did on his air conditioner.
Bay Breeze Compressor Replacement