When you bought your lot, you acquired the living space, which comprises the space between your walls, and a designated parking space, the dimensions of which are onthestrata plan.
It’s unfortunate thT our cars have got larger, but you are only entitled to what is on the strata plan. The owners corporation, can’t do anything about that.
One avenue would be to buy some of the common property adjacent to your parking space and have a larger space.
Remember that apart from the purchase price, you would be responsible for surveyors fees, lawyers fees, valuers fees, to revalue lot entitlements, and then have to get a special resolution passed.
Good luck