You pretty much have to make your own. I would imagine it's like making a slipcover for a chair. Get some brown paper bags, trace everything (in separate pieces), add seam allowances and sew it together.

I'd baste one in muslin before cutting out the good fabric.

I am looking for the same pattern. They sell these on ebay and say they are from a pattern. I need to make my g-daughter a new one. Jenlat, did you come across a pattern to purchase - or did you end up tracing your pattern?

"I need to make... a new one." Can't you use the old one as a pattern?

I didn't realize this post was so old until I had already hit the reply button. Anyway, a lady in one of the groups I belong to just put one on her site at http://www.makethemyourself.com/carseat.html. She has the toddler one available and it's sort of generic so it might work. The infant one won't be ready until later in the month.

Here is a link that might be useful: Toddler Car Seat Pattern