Take a look at Onecnc lathe software. Check out the Onecnc forum here, or at www.onecnc.net
Its a very powerful package for a normal 2 axis turning machine. It allows you to specify your tool shapes and simulate and render the part, too.
You shouldn't have to DNC too many lathe programs. The machine may not have much memory, but its got to have enough to turn out a typical part, I would imagine. Even my old 1Kb ("word capacity") Bandit would run every lathe program I ever wanted.
As for a communications package, Onecnc offers a freebie for that, in case you discover that all you need is a means for the quick upload and download of an entire program.