Why not visit Maleny or Montville up in the Sunshine Coast hinterland. Maybe visit the Eumundi markets while you're there.
I'll second this. Was in Brisbane for the first time a few weekends ago. Brisbane city isn't much, no different to any other city (except the traffic is horrific - we got stuck in traffic jams for 20-30 minutes both days going out of the city and wasn't even peak hour) so we hired a car and went for a drive. Montville is gorgeous, beautiful little town and an amazing view. Definately worth seeing if you're in the Brisbane area.