Don't worry about her getting her own apt. She needs to be out of her dad's house anyway as he's not encouraging her relationship with you any.
Perhaps a light response like, "oh, I'd love to join in on the girl time in Austin. Let's see...we can all go get pedicures, sip dacquari's and just giggle all day. Sounds like fun. Too bad I have to stay here and...(whatever cool guy thing you have planned."
Me 36 Husband 35 D5 S2 separated: 10/29/07-present Served divorce papers 1/22/09 "When the world gives out beneath your feet, it is time to learn how to fly."