Carseat issue

[kscwgirl]

Okay, so I realized on Friday that J is 4 lbs over the weight limit for the car seat that is in my mom's van, my car and Jeff's truck. However, he can't go in a highback booster seat for another 15 months. Any ideas? I really really really don't want to go buy another carseat for him to use for a year and then buy another one, especially since we'd a. have to get 3 of them, and b. I can't find anything that will work at either Walmart or Target.. it's either the seat like I have or a booster...