I would create 5 blockouts for that shape. Try to get the edge loops close to the adjacent geo. As it is you have way too much geo at this stage...Im pretty damn good at curves and the workflow involves very rough blockouts. Keep subdivisions to a minimum...you will add and delete a LOT of edges to get it right. I forgo primitives now and start with a simple poly plane and go from there, trust me when you learn this it will become a lot easier. If you need a quick hand post the ref images here and I will do a basic blockout to show you what I mean.
cheers bullet
bullet1968
"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes