Canoe/kayak

I want to carry a canoe and a kayak (at different times) on my 07 Altima. For Highway driving I tie off front and back in addition to side straps. I have asked my dealer where I can tie onto in the front of the vehicle all they will tell me is "buy the canoe carrier it has everything you need" but they won't tell me if it includes straps for the front (total cost with bars $600 plus) I just want to buy roof bars -not any extra specialized racks becasue sometimes I carry different things (kayak,canoe ladder) Does anyone out there carry a canoe or kayak on their 07 Altima and where do you tie on in the front? Fergus