Upgrade Inquiry

I've been gradually upgrading parts of my system and now it's time to work on the analogue part. My question for the experienced is: Which doI upgrade first -- tonearm or cartridge. My table is an Interspace and I do not intend to change it out --I like it (and I buy into the theory behind it). Any help will be greatly appreciated.
the cartridge usually. the mottingham interspace arm is awfully good, as is the table
i dont know what cartridge you use
but the cartridge mans music maker is a good synergestic and
not stupidly expensive place to start
hope that helps