Is it possible to import a gerber file into Fritzing or do I need to change the format? If I need to change the format, what do I change it too?
No. Gerber is in essence a file that tells a lithography machine how to move to produce the shapes on every layer of a printed circuit board.
Fritzing, on the other hand, is a schematic capture tool of sorts. There's no way back from a pcb layout to a proper schematic, since that layout contains zero information on the components that are supposed to populate that board.
And even if there were any such information, then going back from a layout to an intelligible schematic is still an unsolved problem, and probably will be forever.