hi there is your car a mk1 punto or a mk2???
if its a mk1 punto then the mirrors are held on by 3 bolts with hexagonal heads that you can use a allen key on. they come off pretty easy you just have to prise of the plastic trim to expose them.
if its a mk2 its harder because then wing mirror is held on with a ringnut that fiat have a special tool for.
2001 Punto sporting in sprint blue with matching Mr Bump air freshner all together now mmmmmmm