I have a judgement against me. I'm married but the credit card was just in my name. I want to pay this in installments, but I'm not sure if I should contact the original creditor or the collection agency? Does it make a difference?

You would pay whoever has the judgment against you. Do not send them payment by check, they will granish that account as soon as they know where it is.

They may accept payments from you, but don't count on it.