Carol's an energy absorber. Her power levels will fluctuate upwards wildly depending on how much she has spooling around inside her. So some days she might be more powerful than Thor, mostly I'd guess not though. Like pretty much every other super-strength character though her power level flux mostly due to authorial fiat - in other words it depends on what the writer needs her to be able to do for the story.
Note: the only people who think she's ever been hanging around below She-Hulk levels are the turbonerds who start referring to the stats posted in RPGs and so on. Those things only get put in to appease the 'power ranking!' autists and are less canon than even anything Bendis thinks up.