I'm not sure about the order in which the files are called, but if you type or paste the following commands into your Terminal window, that should cover most of the bases.
[codex]cat << EOF >> ~/.profile
PATH=/sw/bin:\$PATH; export PATH
EOF[/codex]
[codex]cat << EOF >> ~/.bashrc
PATH=/sw/bin:\$PATH; export PATH
EOF[/codex]
[codex]cat << EOF >> ~/.bash_profile
PATH=/sw/bin:\$PATH; export PATH
EOF[/codex]
You also should open a new Terminal window afterwards for the settings to be recognised.