.zip file troubles

I downloaded a $70 wordpress theme from woothemes. i got a file full of css encoders and php files and other random things, but no .zip file. I also tried to install a Plug-in from a different site and that also downloaded as a big file with no .zip file in it. i’m using a mac, and i have the latest version of wordpress. how do i find my .zip files/how do i convert a .php file to a .zip file without spending more $$?