Okay are you saying 18,000/year after taxes and expenses? I'm just going to assume no taxes. 18K/year works out to $1500/month. Subtracting out all the expenses you listed (plus a very conservative estimate of $50 for your monthly phone bill), that leaves you at $605/month after rent, phone, car notes, and netflix. That comes out to $151.25/week. According to the US Dept of Agriculture, the minimum cost of feeding a family of 4 a healthy diet is $146/week (published in May of this year).
http://www.usatoday.com/story/news/nation/2013/05/01/grocery-costs-for-family/2104165/
This means you have just
$5.25 left each week to pay for everything else. We haven't even considered any of the following: bath & grooming supplies, cleaning supplies for the house, car maintenance, car insurance, doctor visits & checkups for the youngsters, daycare costs, clothing, and probably a zillion other things it's important to provide for a young family. Presumably you are also debt-free. Am I missing something here??? Are you receiving federal or state aid of some kind that is helping bridge the yawning gap I have identified? Or were you deducting these costs prior to the $18,000/year total? Either way, your initial post is extremely confusing and I would appreciate it if you could clarify.
ETA: and where are interview expenses fitting into that $5.25 weekly budget??