I don't have advice on specific hotels, but my standard advice to traveling ladies is this:
1. Avoid downtown. Too expensive, too much traffic.
2. Avoid Williamson County (
Click here for a map of the county line and regions.). Law enforcement can be more of a problem up there.
3. If you want to be close to the nightlife, pick a location south of downtown.
Additionally, Austin's traffic makes it somewhat difficult for guys on one side of town to meet ladies on the other side during peak traffic hours. If you choose to stay & host somewhere in north Austin, expect to hear complaints from the guys in south Austin, as most will be coming to visit you during hours in which traffic through downtown is pretty bad.
Most hotel search engines allow you to search by zip code. Try 78745 or 78741 for South Austin, and 78758 for North Austin.
If you decide to choose a hotel in the IH35/290/183 intersection area, I would recommend *not* leaving any visible valuables in the car. Austin 'mongers nicknamed the area "The Vagina Triangle", and consider it a rather seedy part of town to visit for BCD purposes.