First thing is…. Plz don’t rush to change the wheels unless you fully know what is the best & perfect replacement of it.
Secondly, open the drive door and check the sticker on the door jam. Exact wheel size will be written there. Plz post that photo here and then you can expect the best advice from these forums.
BTW, many varients of yaris came with slightly different size of wheels. So first thing you should know that what is the actual wheel size recommended by OEM for your model of Yaris.