All of those questions were answered on the Sprite Stitch Blog interview!
Seriously though, the time it takes depends on the quilt. A quilt could take anywhere from 2 weeks to 3 months. This quilt took me 3 weeks. It is very expensie for quilting. For example this quilt cost me $180 in materials alone. I sold it for $250. so $70 for 3 weeks of work isn't a lot. My machine is also a $3500 machine that can handle the quilting on a daily basis.
And yes, that is all I do is sell my quilts. I do conventions, but mostly commissions. I make some as gifts, but don't end up keeping any of them. I don't make money, ust enjoy doing it.