If Padme has to die in that time frame we could give her a more tragic death (rather than selfish one we see in ROTS).

Palpatine claimed that to have the secret of bringing people back to life (physical life as contrasted with the Jedi spiritual return in the form of a Force ghost).

What if Anakin literally died after the fire, which make Obi-Wan less of a git for leaving him to burst in flames.

Palpatine brings him back from the dead but to do that he pulls the life out of the person he loves most of all (besides himself) Padme.

It sounds like the sort of sick way the dark side would work, to bring someone back you have to kill someone they love.

In fact you could still adapt the idea into a longer death for Padme, the spell (for want of a better term) could work so the stronger Vader becomes the weaker Padme gets so if Vader's recovery is long her death could be drawn out too.