First, I always say to "start with yourself" and be a role model for living frugally - which means that you don't get the new CD of your favorite band (even though your hubby just bought a comic book) - you need to show strength and restraint. You really need to set an example for your family. This also includes buying things for your DS. As amazing as he is, he probably doesn't NEED a whole lot to make him happy. I'm guessing from your post, that you don't work outside of the home, is there anyway that you could babysit or something to bring in a little extra cash?
Also, you really need to get your DH to realize the mess you're in. You need something that will visually remind him. I would suggest that you make a graph of where your finances will be in 1 year's time running on a deficit every month - it will be more than 7k. Then, you say, but the good news is that with some changes, we can prevent this from happening. Then you lay out the changes (go for the least painful ones first that will make the most impact - and start with yourself!).
Then, on a weekly basis, I suggest that you make something visual (graph, Excel, or hand drawn) that shows: this is the money that is coming in this month, this is what we've spent so far, this is what we have already committed for (budget of rent, electricity, credit card, etc.), and this is how much we are projected to be over/under. This will easily identify the fact that you don't have any extra $$ for comic books or whatever. This will help in a conversation with DH on where you guys decide TOGETHER what areas need to be reduced (food, electricity usage, gasoline, etc.). You need to be a team.
You are running so close to the edge, you can't do this alone, you need your DH's support and commitment to getting your finances back on track.