I believe the part is sometimes called the beltline weatherstrip. CJPony sells individual pieces or a kit for all 4 of the side windows.
No no he is right I was able to find those:Nobody sells beltline weatherstrips (aka windowfelts) as individual pieces, because none of the manufacturers will sell them individually. They can only be purchased as a kit. Besides, if the 1/4 windows are toast, the door windows probably aren't far behind.