Personally, rather than drawing with curves I would have just molded it straight up from a polygon cube, but rather than let your work go to waste:

You can use the curves as references and just extrude faces and drag vertices into place, or actually extrude the faces along the curves themselves.

Then again you could try using revolve (in 2008 it's Surfaces>Surfaces>Revolve and in 7.0 I believe it's Modeling>Edit NURBS>Revolve) and messing with the options for each curve so that they revolve the proper amount, though this can be tedious.

All in all I'm not particularly good with NURBS so you may want to wait for someone more experienced to give a better option. I'm interested to hear how others would solve this problem.