Currently Being ModeratedDec 4, 2012 6:50 PM (in response to kjo20)
Leopard is 10.5.x, the one your mac should have origionally came with. You can upgrade to as high as OS X 10.7.5. You mac is not capable of upgrading to the newest version of OS X, 10.8, due to hard drive restrictions.
Currently Being ModeratedDec 4, 2012 7:19 PM (in response to kjo20)
The 10.6 Snow Leopard DVD is back in the Apple online store. You can get it for $19.99. http://store.apple.com/us/product/MC573/mac-os-x-106-snow-leopard