First of all, clarify exactly what you are buying.
1. A set of winter-tires only OR
2. A set of winter-tires on rims (tires + rims)
For "1", nothing to worry. The set you are buying will fit your current rims.
When it's time to change tires, remove the current tires and mount&balance the winter tires.
For "2", if you don't care to use the rims come with the tires, which means you only want the tires, you treat it same as "1".
For "2" and you do want to use the whole set (tires+trims) that you buy, then this set is not for you because the rims will not fit your car.