new celica gt-s

I recently bought my first car a black 2000 celica GT-S 6spd with a little over 108k miles it is all stock except for the after market radio and wheels. I love the car to death it handles like a go kart and sounds really nice once you get it past 3k rpm. But there is only one problem one of the wheels are broken and although it is safe to drive on i just dont like to see her sit on a broken wheel so does anyone know where I can find a 16 inch motegi mr7 wheel. Also can i bump up to 17inch wheels all the way around to close the wheel gap and better the handling?
oh and i payed $4300 for the car