Is any of this back story pertinent to the case? Should I inform the court?
Not really.
Can I be arrested/otherwise additionally penalized for my situation?
If you a subject to a child support order and don't pay, but have the ability to pay, you can be held in contempt of court and incarcerated until you do pay. If you are unable to pay, this is a legal defense to contempt of court and you should not be incarcerated.
The court could also reduce the arrears to a money judgement if this hasn't already done and place liens on your real property and authorize seizure of your personal property to pay the debts.
The court could also order you to disclose the location of all of your assets and income.
What can I expect when I go to the hearing?
There isn't enough information in this post to be very clear exactly which stage of the proceedings you are in. If you be an advisement and a setting of a hearing later on the merits, it could be a hearing on the merits itself.
You should be prepared to prove that you are unable to pay, or if you are able to pay, you should do so before the hearing.