Car Seat (Dunedin - Patricia & 580)

With 2 grandchildren, 2 grandnieces, and 2 grandnephews four years old and under, I could use a car seat. One of the 18 month old grandnephews is visiting May 29 for four days.. The 2 grandnieces are twins so having two would be an asset. And my grandson is 2.5 years old and his sister will be born this fall. I would need two when they visit next year. So, if you don't have anything now, but might have something later on - keep me in mind.