If they answer your questions satisfactorily, I'd go with the new job. I know money is often an issue with your family's situation, and having more of it will take a lot of stress off everyone. And just because it is a different company doesn't mean you will be miserable there - after all, they came looking for you, I think they deserve the benefit of the doubt! With the current economic slowdown, and because your current job involves commission, things are likely going to get worse, money-wise, before they get better.

Only you can make the decision, but I'd say "go for it!"