I've also stayed at the Le Saint-Sulpice, which is very expensive but nice. A few years ago, I stayed at a hotel near the Palais de Congress, and I know I liked the hotel, but I can't remember the name of it. I'd advise trying the Priceline strategy to get a good hotel at 50% off.

I have also run into the same issue when traveling solo (I'm going to a conference alone soon, and I want a private room, but that makes it doubly expensive – so frustrating!). Sometimes I wish that hotels had single rooms with one twin bed.

By the way, I live in Austin and I'm the About.com Guide to Austin (Austin.About.com). Let me know if you ever have any questions! My dad actually used Priceline last time he came in and ended up getting a room at our nice downtown Omni for a steal.