Just a tip to get your child's car seat checked, usually clinics or hospitals have times when they'll do it for free. carseat.org has more info and links to organizations too:
A recent press release from the Prince of Wales Medical Research Institute is bringing attention to the increased risk of death or injury to children through the use of car restraints that are the wrong size or are improperly secured.
Considering that automobile accidents are one of the main sources of traumatic brain and spinal cord injuries, understanding how to properly secure your child becomes a vital bit of knowledge.
full review here:
http://www.brainandspinalcord.org/blog/2008/07/poor-car-restraints-risk-kids-lives/