/usr/local/pgi-7.0.4/linux86-64/7.0-4/binin your PATH environment variable. (One convenient way to do this is to include the appropriate assignment in either your .cshrc, .profile, or .bash_profile file according to your login shell.)
With bash, for instance, you would say
export PATH=${PATH}:/usr/local/pgi-7.0.4/linux86-64/7.0-4/binThen, from the command prompt, type
source .bash_profile