If you ABSOLUTELY AND UTTERLY have to stick with your car, you could always get NO2..........but, you really should let your insurance know and as soon as you say the word "Nitrous" to them, they will s**t.
A 1.2 is NEVER going to stir the soul, even with 100 odd hp of Nitrous up its arse.
I appreciate insurance difficulties at your age but enjoy the car for what it is and enjoy the freedom it gives you. Save and aim higher as soon as insurance works for you. Dont be impatient and make the 1.2 into a car that cannot handlke it and be lethal......the brakes are the gayest thing on earth on 1.2's
Jj