Hubcap question 2009 Yaris Sedan- URGENT

[mrs_yaris]

Hello

I am a car novice but I am utterly in love with my car so I am posting here after having exhausted my limited knowledge on cars and after extensive google search.

I have a bit of a basic question. I have a 2009 Yaris Sedan base with 15' wheels. A few days back one hubcap flew off my wheels while driving. I am now trying to buy a replacement wheel cover and I am confused about the options available. The original hubcap is a 8-spoke one with 4 lugnut spaces. Most of the replacement covers I am seeing online have NO space for the lugnuts.

My question is,

1. Is the lugnut space cosmetic and will any 15' wheel cover fit on the car- with or without the lugnut hole?
2. Will I be able to replace the cover myself at home given that it has this lugnut thing going on.

I don't trust my tire place to do it because they are the ones who put in on loose when they changes my tires recently.

This is what the original wheels look like