1. You can mine with just your mac and nothing else using DiabloMiner. Nothing will really increase your chances of success.
2. Solo mining is just a matter of what setting you select so.
There is a small chance you could solve a block by yourself(extremely small). The real problem is that mining will burn out your hardware turning your mac into a lovely looking brick.
If you only have the address it is not possible to recover the private key. The private key is what is important. you can extract your private key from a wallet.dat using pywallet. Look here for details.
You should copy the entire ~/.bitcoin/ to ~bitcoin-test/ cp -Ri ~/.bitcoin/ ~bitcoin-test/ then I am sure ~/.bitcoin-qt -datadir=~/bitcoin-test should work.