I need to find out what to do for court. Paternity testing question.?

I was ordered by the referee to pay for the paternity testing of my youngest son. My soon to be ex husband works, makes more money then I do and lives with his parents. I take care of both of my kids, by myself and I'm struggling to make ends meet. I didn't get a lawyer for our divorce because I don't want anything from my ex husband. I cannot afford the 525$ to get paternity done. What do I do? I literally cannot afford to get a lawyer, or the test it is way out of my budget and I think paying rent and putting a roof over my kids head is more important. My question is what do I do now? Do I go back to court in July and just tell the judge that I can't afford it? I don't know if I will get into any trouble either. Any help would be great. I live in the metro-Detroit area.