You might be able to set it up through Scheduled Tasks (depends on how the program executes itself). Just create a task with the time you want it to start. When finished, right-click on the task, click Properties -> Setting. Click the box for 'Stop the task if it runs for.....' and put in however long you want it to run.
Or, you could download another client that has scheduling tasks already built in (ie. uTorrent).