I don't think there's really any easy fix to suddenly turn it around in free agency. It would take a big blockbuster trade to really change things and that moment is long gone. Nylander and Rielly are locked up for ever with NTCs and Marner and JT are either walking or re-signing, and no one in free agency are as good as they are.
They should just commit to this core as much as they can regardless of how they do in this post-season, and see what you can do for a few more years. It's not exciting, people will cry about it but it's the likely scenario.
I'd look at selling high on Stolarz, as high as possible anyway, and cutting the passengers like Kampf, Jarnkrok and probably also Domi for as little cap back as possible and finding alternatives via trade/free agency.