I can imagine that missing your family and feeling like you can't put down roots is very hard for you. But here are a few points to consider:
1)You're upset because you'll be in your 40s when you get home, but honey, 40 isn't the end of your life, lol!
2)Living in the States is not going to be the life you want for your family if you are financially not sound. Personally I am out of work and our mortgage is underwater- I would jump at the chance to live overseas for a few years if it would make us more financially solvent at this point! You don't want to live here and not be able to give your family the quality of life that you need!
3)What does your husband say? Does he want to take this new transfer? The two of you MUST come to a decision and at the very least present a united front about it, or your marriage and your family could suffer for it.
4) You have unopened wedding gifts back home?? Why? Get your mom to ship you one or two things at a time so it isn't too expensive and clear up those things. It sounds like your everyday life has not been in the States for a while and you can't keep looking at where your family is as a sort of 'not your real life' .
Where ever you are in the world, you must make a home for yourself and your family- and remember, to your children, where ever you are, IS home. Home is with your family and the people who love you and you have to instill that in your kids. I know you love your family back in the States, but don't let that poison you against doing what is best for 'your' family. Focus on the positive- introduce your kids to new places and cultures and remember that home is where ever you make it.
I am sorry you are going through such a difficult choice- but remember there are thousands of out of work people here who would love to have an option or choice like that. Do what will be best in the long run for your entire family and talk with your husband and make a decision together. Good luck!!