Enigma, TAFE isn't exactly college, it's like entry courses for uni.. and trades etc.. not that it really matters..
anyway, Mike! I suggest that the next time you're in the cafe or whatever and you see her .. whether she is by herself or with her friends, just go up to her and say hi, and ask for the time .. that's seriously all you need to do.. get the time and say thanks and walk away.. IT IS AS SIMPLE AS THAT.. you're pretty new to this so baby steps.. you dont even need to THINKG about going up to her and starting up a conversation ... YET
leave that for another day..
Just remember to have good eye contact when you're asking her and make sure you kino her when you're saying hi, just to get her attention..
After that .. you may see her the next day walking towards you .. all you gotta do is say "hey how you goin!" and possibly add something about the time .. "you know you saved my life there yesterday by telling me the time ..

" .. and she'll be like.. "oh really how!?" "uhh.. i'll tell you later .. how's your day been?"
and there you have it .. you've started a conversation with a person you pretty much just met the day before!!!!
and if later on she asks you about how she saved your life.. that is a HUGE ioi .. (indicator of interest, just incase you dont know the lingo yet

)
good luck buddy..
hit me up with a pm if you need .. im in brisbane too
peace