Pregnancy: Toddler, Graco Safeseat

Help with Crooked Carseat

So I have a Graco SafeSeat for my baby who is now 12 months old. It is rear facing and goes up to 30 pounds, so we will be using it for a while longer (my baby is around 20 pounds). My problem is that the base is installed in the middle backseat of my 2001 Chevy Prism, which doesn't have LATCH thingies (it has them on the sides, but not in the middle), so it is installed with the seatbelt which is a shoulder belt, and when I pull the belt as tight as it will go, it pulls up on the side of the base because of the shoulder belt. Does that...