Well, looks like you are pretty worked up for nothing. I understand how you may feel very frustrated and have someone stepped on you, but I spent some time to think in your shoes and here is what I am thinking (you might thought about that already but hear me out):
These are the problems I've identified based on what you posted:
1. Dead car
2. Your only car is also dying
3. No job for you
4. 2 kids you can't afford to put in day-care
5. You are pregent
6. Living with your mom giving you a lot of grieve
7. You need some extra money... quick
First ofall you should revisit your budget... Yes, yes I know you've already done that many times, but do it again... I don't know what structure you are currently using, but based on your current situation how about:
List all your credit payment out (CC, car payment, insurance, loan repayment)
Then you have what's left to spend on essentials... (Diapers, food, gas, etc.) Now visit all your previous spending on these essential items one by one and see if you can find a better deal (Instead of Micky-D meal for you and your kids, try only ordering dollar menu items; or no Micky D; Instead of brandname diapers, try a cheaper brand or wait for it to go on sale if you can... This can go on and on)
Then, go to some non-profit organization who help tight budget family like yours in grocerys, insurance, debt consolidations, and see if they will be of any help. (I know, living on food stamps doesn't seem to be very dignifying, but remember, you'll only be in this situation temperory and you'll be back on your feet sooner than you think)
I forget if you mentioned debt consolidation yet, you can also call your creditors and explain your situation to see if they'll cut you some room here and there (a dollar here might not seem much, but every penny counts at this point!)
I don't know how much you are making from your home-based business, if it's not helping much, try going through some newspaper and find some part-time jobs you can apply for (admin. assistant or temp. clerk) Since you have experience you're better off in this situation because its just a temp. or part time position anyway, who knows, you might found an employer who is willing to work with your situation simply because he knows you can get your job done while you're working...
In terms of your broken P5, see if your brother can help by letting him tow and fix it, see if you can borrow some money from him (cuz sounds like he might be able to do that with his skills, etc.) If you are able to do that, get it fixed and SELL THE CAR... Take the lost now and get another used-car so you can buy minimum insurance and give more room to your budget... Yeah, you might shell out money to fix both cars, but at least the expense is still lower compare to keeping the P5...
This is my sincere thought and I hope you don't feel like I'm trying to school you or anything...
