Without buying more memory or DNC-B you will be limited on the size of program you can run. Your management data card should show how much your machine has. It's possible to use MD0: for additional storage but don't fill it up or you may run into trouble operating the machine.
The workaround is to use the schedule program feature of the machine. It will allow you to break the program into segments and then run them by schedule program.
RUN.SDF (file name)
PSELECT A.MIN,,,Q1
PSELECT B.MIN,,,Q1
PSELECT C.MIN,,,Q1
END
Break program into sections a,b,and c and then instead of program select use sp-select to call up RUN.SDF. It will load and unload to memory allowing you to run as much as you can store.