You’ll hate me for saying this, but your question reminds me of my grandmother’s old saying: “You can’t get blood out of a turnip.” I don’t know how you’ve even managed to save as much as you already have! Congratulations on that. But the real solution is to bring in more income. Now that the kids are in grade school, could you consider some sort of part-time job. You could put away all that extra income in a Roth IRA — where it would grow tax-free for retirement. College is another story. They will likely have to live at home and go to community college, and rely on financial aid — which will be a lot different in ten years, that’s a good bet.
Please figure out how you can bring in some income — and then write back to me, or send me an email and remind me of your question. I will be happy to help walk you through the process of setting up a Roth IRA when you have at least $1,000 saved for that purpose. You can do it!