You probably know the year she graduated, you can run subsequent queries using +-1 based off of that graduation year. What you're after at first are rosters. The end goal is to place a picture for each name discovered.
Over 10 years since high school graduation? I'd be looking at one of the classmate or facebook groups regarding reunions. Less than 10 years since graduation? I'd still look trying to compile a list of names from these places. Old high school sports and club rosters maybe? Build a graph of people who did go to that high school during those years. Start building 1 degree of separation.
Once you've gotten a list of names, start cross referencing local groups, meet ups, colleges starting with the University of Texas -- possibly even spamming people using generated you've collected )lastname_firstletter@utexas@edu). Perhaps a phishing Email as follows "information regarding blah blah, looking for the person in this pic, we think they left their purse/cell phone etc"? Or post something in a local Austin Reddit.
I'd also do simple searches based on individual names and generated college emails. Start cross referencing all college clubs past/present with names and/or generated emails. If the person is/was in graduate school they will probably have even more school related information online.
If the person has graduated, start working the job route. Online career profiles monster, linkedIn, facebook. Have they done any sort of volunteering? Lot's of pics associated with volunteer work are out there.
5K results are a treasure trove, location, name and age ripe for searching. Some 5K's have corresponding flickr sets where you can match name to race number to a face. Once you have faces either look at them or run them through some CV for possible matches. Even if the name you've found isn't the person you're looking for such pictures might lead you to them anyway, if that person appears in a picture with your target. If you know that the person you found knows your target, start looking at that person's information. Who do they follow on pinterest, twitter, etc...
Does this person own a house do searches against the tax databases for full address of home. Even if the address isn't useful you might learn their middle name - re search with middle initial and middle names in lieu of first names.
Look at old social networking sites like myspace - the target might have old profiles up?