You mentioned an IR1 visa for your husband and probably IR2 for your child. As mentioned by Jan22 your son is now a USC he just needs to get his passport.
Your husband is allowed to work right now, if he came in on an IR1 visa. The stamp in his passport is his temporary card. If you decide to give up and move back to Peru he would give up his permanent residency.
For your mom, she can come visit. Do not say help take care of your son as that would fall under babysitting and not allowed as a visitor. She can be a Grandmother and spoil and spend time with her grandchild. What she does during that time does not matter. But she cannot be a babysitter as that would be taking a job and not allowed.
So on to your expenses. You are living in one of the most expensive places to live in the US. If once your husband finds work (once he gets his SSN) and things are still too tight. Looking into moving, the US a big country, there are so many places that the wages better match the cost of living.
My son moved to Washington, because he was enticed by the wages there. Sadly being young and dumb he forgot the cost of living is at least 3 times the amount of living in Arkansas. He has to have roommates just to keep a roof over his head.
Since you pretty much just got back to the US and the shock of the cost of living and wages just hit you. Take your time, once your spouse finds work, re-examine the costs and make a plan to either find a better paying job, or better job and location. Weather that means leaving the state you're in right now or just moving around in that state that works better for you.