UAC will only stop considering you for another offer in a future round if you have already received your number 1 pref in an earlier round (and you did not change prefs to reorder a different pre to number 1). (You have to meet the ATAR of course!)
Hence if you got pref 2 in early round it is possible that you could get pref 1 in a later round. Of course, if you didn't get pref 1 in the early round would suggest you didn't make the cutoff in the early round, and therefore you would only get pref 1 in a later round if the cutoffs go down between rounds. Another possibility is that the uni was not making early offers to the course which was your first pref.
You know your atar and you know the cutoff for your course last year - did you make it? ATARs dont change much year to year.
Suggest you visit
http://www.uac.edu.au/undergraduate/faq/offers.shtml