Do you live in the suburb South Brisbane or do you live in the Southern Suburbs of Brisbane.
If you live in South Brisbane (the suburb) Kangaroo Point cliffs stairs are used a lot, I've done them, close to South Bank. West End is pretty flat so me thinks you'll have to venture over towards Dutton Park/Highgate Hill - goat country.
Just chuck the joggers on go for a run around your local area, usually a hill or road with a hill somewhere I've found.
EDIT: Do Mt Cootha (or should I say it'll do you)