This election (2006), Andrew is standing as a candidate for the upper house. Upper house members represent the entire state, they don't represent small specific areas (electorates) like the lower house does (the House of Assembly). You can, and should, vote for any candidate that you prefer for the upper house.
Whichever party dominates the lower house determines whether we have a Labor or Liberal government, you don't have to vote for a candidate from the same party into the upper house if you want their party in power. And, in fact, there are good reasons for voting differently between the upper and the lower houses:
The upper house can act as a regulator against the political party dominating the lower house. If a single party dominates both houses, they can get away with just about anything that they want to. But if they have opposition in the upper house, they're forced into behaving more responsibly if they want any chance of getting their bills passed through.
NB: For more information on how the upper and lower houses work, you can consult the State Electoral Office's website.