IMO... the cheap way would be to drill a new hole in the botom fairing that is cracked and zip tie it with a black tie.
You could try an putting a rubber type washer or grommet around the side screws but it would be dangerous if you think the fairing could vibrate off. again you could drill a small hole in the sides and ziptie for safty. But it would look pretty busch league.
Best bet is to buy used fairing off ebay or ask around to see if someone converted their CBR to a race bike and see if they want to sell their stock parts.
hopefully someone that is good at fabricating will chime in
