Can You Help Me With An Ethereum (ETH versus ETC) Question?

I purchased Etherum in the original crowdsale and haven't done anything with it yet.  I still have the original JSON file, password, etc. provided during the crowdsale.  

I'm thinking of moving my ether to a wallet sooner or later.  

Anyway, my question is this:  Do I essentially have both ETH and ETC at this point?  If so, do I need to do anything in particular when I move the coins to keep them both? Anything I should be certain to AVOID doing?

Thanks for the guidance.  I'll upvote good answers.