Adding K&N goodies does little other than gain 1BHP and make some noise on the HCS engine.

To make significantly more power you'd need to go nuts porting the head, swap the cam for a race spec one and add twin carbs.... or go forced induction. All very expensive....

On a teenage budget the best way to go faster is strip the car to within an inch of it's life.
Complete interior out, sound deadedning scraped off, interior frameworks cut out of every opening panel, plastic windows etc etc....

Go the whole hog with either route and your 60BHP will be more like 100BHP, but one way will be a LOT cheaper...