Hi Chris,
I recently replaced my old Lenovo laptop battery with a new battery from Better Batt in Victoria (
http://www.betterbatt.com.au/).
Their prices and service was great and the new battery was delivered interstate the next day.
When I plugged the battery in it said it was a Sanyo, so their internal components seem to be good quality.
I was also happy to support an Australian business. If you are looking for a new battery, it would worth checking out their website.
Cheers,
Mark