Well... I'm not sure how helpful I can be, but I'll try.
I'm living with my mom, too. People have placed a stigma on this, but that's stupid. Families need each other. I'm sure when your babies grow up you'd be happy to help support them, and I hope your mom is the kind of person who is willing to support you and help you through this time in your life.
Even the news is starting to admit that it makes sense for people to have extended family support networks. And it's not new. People used to live with their parents for WAAAAAAY longer than they're "supposed to" now.
It's a good thing, so be glad you have the option. Some people (my mother) end up trying to keep their babies warm in apartment stairwells because they have no place to live.
And I know you've already got an eleven month old, but if you do it right, babies aren't all that expensive. I hope you're breastfeeding, because formula is RIDICULOUSLY expensive. I bet if they stopped offering it through WIC, the prices would go down, because nobody can afford it without WIC. Besides, it isn't healthy for the babies, and it's so much easier to roll over at night and feed your baby instead of dragging yourself out of bed to heat up a bottle.
Baby clothes, toys, blankets and so forth can be bought at thrift stores for next to nothing. I pay less than two dollars for each of my daughter's outfits. And there are groups you can search that might be willing to give you used strollers and such.
SAVE what you have if you can. Save the 450, too, if at all possible.
I'll bet the only reason you can't find a job is because no one will hire you when you're pregnant. They don't want you on their insurance. Cold, but true. I had the same problem.
Well, again, if your parents are supportive, count your blessings, spend time with your babies (they'll only be babies once). Give your parents the 450 for rent if they need it, but save that 700.
You can always get a job when your kids are older.