Smart Lipo won't fix your loose skin
Without even seeing you, I can tell you almost for sure that if you have loose and stretch-marked skin after two huge babies, nothing non-surgical available today will tighten you. Period.
And BTW, smarlipo is surgical. Though the company touts it as being non-invasive, it is even more invasive than regular lipo.
So if you were open to that, you should be willing to consider a tummy tuck. If you care enough to write a question to this website, then at least get a consult with a board...