I had a judgement awarded against me in 2005 for the amount of $4022. I am almost finished paying for the amount and now I am told by the law firm that they did not add interest fees and I now owe another $1200 - 3 years later. Is this legal? If they did not ask for legal fees and interest in a judgment, can they come back and ask later?

Do you have a copy of the judgement? It typically states it's for $XXXX amount, plus court costs, legal fees, interest in the amount of XX% per year, etc.

It should state clearly in the judgement exactly what they're entitled to collect. Not specific dollar amounts, but categories of fees. If you feel that specific fees are unreasonable I would contact the court that issued the judgement.