FME is not one I'd expect to see. It's more likely SMA.
Look at the gold coloured end of
this adapter. Does the N300 end look like that?
The antenna is supposed to screw into the socket on the N300, what is broken? Is it the antenna or where it screws into the N300? If it's the antenna then you're OK, if you've damaged the N300 itself, then you're in a worse place.
It looks like you've broken the part of the antenna that screws into the socket on the N300. That part is pretty vital because it makes one of the connections between the antenna and the N300.
A replacement whip antenna may be the easiest fix.
I would connect the antenna to the dish using cable ties through holes in the lip of the dish. A plastic standoff could be used to ensure a reasonably rigid arrangement at the "free" end of the whip.
Get it all done with the antenna NOT connected to the N300 and then connect them together. Looping the USB cable to the N300 through a cable tie connected to the dish would help reduce strain.