editing a pdf map in illustrator

Hello i got a pdf of a map in which all layers (streets, rivers etc) are nicely organzised in layers. I need the map in different colors and sizes and it would be nice if i simply could import it in illustrator an work on it. When i open it in illustrator, all layers ar in a mess. And although i can deselct and not view certain layers, in illustrator all are displayed again. Plus: the lines (streets for example) are not lines anymore but objects... any tipps?!