Okay - here are some random suggestions...
Friday afternoon
- Botanic Gardens, Brisbane City
- Ferry Ride to New Farm, and then back down to Southbank
- Markets at Southbank at night
Saturday
- Hop in the car and drive to the Eumundi Markets (about a two hour drive north of Brisbane)
- Drive back through the Blackall Ranges passing through Maleny, Montville and Mapleton. Stop at Colin James Fine Foods at Maleny for lunch and an absolutely wonderful pumpkin soup. If you come through Maleny you can get some excellent shots of the Glasshouse Mountains, or you can detour past Steve Irwin's crocodile park and get some nice close up shots.
- Once you come down off the ranges and back to the highway you can head across to the beaches at Maroochydore, Mooloolaba and Caloundra. Noosa these days doesn't have a lot to recommend it. Alexandra Headlands will give you a good opportunity for surfing shots.
- Heading back to Brisbane you can stop at Bribie Island or Redcliffe, both of which have a number of interesting areas.
Sunday
- Riverside Markets absolutely first thing in the morning
- Cleveland Markets (you can catch a train there)
- There's also a natural swamp about 600 metres out of the town centre which has some great photo opportunities
- Ferry across to the Bay Islands (hop on and hop off at Lamb, Russell, Macleay, etc) If you go to the top of Russell Island and the boats are racing you can get some great shots of the yachts as they come through the passage
- Back to the Grandview Hotel (or the Redland Bay Hotel) for lunch. Both have great views, but the Grandview is a little more upmarket. If you keep going past the Grandview there's a small lighthouse and if the tide is down you can walk across to a small island (or get shots of families walking across to the island).
Weekdays
- Mount Cootha early in the morning, which gives you a nice view over Brisbane
- Mount Cootha Botanic Gardens for great tropical plants and flowers to give your macro lens a workout
- University of Queensland for some lovely sandstone buildings
- Dinner at Cha Cha Char (steak) or E'cco or any of hundreds of other restaurants depending on your preference/budget.
Other Random Stuff
- Gold Coast (I'm sure there is someone who knows more about the best places down there)
- If you like historic buildings, Parliament House has regular tours
- The old Queensland Museum at Spring Hill is one of my favourite buildings. Spring Hill, Paddington, Fortitude Valley, Tennyson and West End also have a lot of interesting architecture.
- If you are heading down to the Gold Coast, Daisy Hill State Forest is only a short deviation, and the education station there has koalas inside the building (as well as roaming animals outside). It's really good for overseas visitors, because you can stop off, say "There's your koala!" and be back on your way within ten minutes.
- The Kangaroo Point cliffs are a great spot for photos. They're lit at night, they have strange people with ropes on them when they're not lit. At the bottom you can get some shots of the river and at the top some shots of the city.
If you have any other questions...