My personal preference for Diana's absolute extent of her physical powers is in the multi-planetary to solar system level. I'm gonna ignore her other powers like her love empath power from Aphro, Zeus's universe busting lightning, Hestia's divine fires, Athena's multiple different gifts (wisdom, grey eyes, etc..), her godlike senses (maybe more then just the five), and a whole host of other ones. This is just what I think she has shown to be physically able to do.

Strength
Raw -> large planet level to star level
Striking Power -> multi planet level to star level
Durability
physical -> star level
magical -> highly resistant (like it takes some serious magical power to hurt her, no two bit magician is going to affect her for long)
energy -> highly resistant (it takes a massive amount of energy to hurt her)
molecular -> highly resistant (like no one can turn her to clay or transmute her in someway)
elemental -> immune to natural fire and ice (i.e. she doesn't get cold or hot)
mental -> near immunity (there was a time were high level telepaths couldn't even effect her)
Healing Factor -> she can heal herself from death's door in a week tops (unless she's effected by some poison from the good Dr. )
Speed
Travel -> faster then light
Reaction time -> Femtosecond to attosecond (comparable to Flash)
Combat/Reflexes -> massively faster then light

When I say absolute, I mean this should be Diana when she is giving it her all or holding nothing back.