T.F.
I usually buy my nice dresses at Neiman's. You can find some very nice dresses and they are not as pricey as you might think. They have several price ranges. I think I spent a little over $200 for the las tone I bought there.
Special Occasion dresses is located on Preston Road. THey have a lot of dresses. If you are on George Bush TOllway, exit Preston and go south. They are located within a couple of miles from there on the right.
Good luck finding what you like!