I would advise downloading a copy of Freescan and using that to get the system from the Radioreference database. You probably will need to buy a converter for serial to usb unless you have a spare serial port that will take the Uniden cable. The database here has 24 trunked systems and 30 conventional ones for that county in your state. It will cost you $15.00 for a six month membership and maybe $30.00 for the converter if you need one.
The Freescan software isn't the ultimate, but I was able to figure out how to use it to install systems without having to go to the help files.