OK that wheel isn't that old. it shoud do the job ok.
Inside sim racing did a review of that wheel that could possibly be helpfull
http://www.youtube.com/watch?v=6lwfSUKnmqI
Did you check those settings I mentioned above? they might do something for you.
And if you're looking to slide around a bit make sure to turn off the skid recovery force and Traction contoll along with ASM (turn eveything off but the ABS).
EDIT: At the end of that video they metion that its not PS3 compatible, so that might be the issue.
Ok more searching brought this up
https://www.gtplanet.net/forum/showthread.php?t=221881 looks like a GT5 update killed this wheel.