I have a toddler who can't walk far and a newborn due in a few months. I am hoping to get a cheap possibly second hand double pushchair of some form for when we go on long walks. I would need it to have one side where a car seat would attach and the other to be a pushchair seat for the toddler. Does this exist?? (i don't know anything about pushchairs) and if so what do you recommend? x