"My way or the highway" is an expression from words in a song. This line means: "Do it my way or I'm out of here – I'll be (or maybe you'll be) on the highway, but we won't be negotiating or accommodating to each other." It refers to the words of a person who barges ahead, carrying out only his/her agenda, with no regard for another's. It doesn't matter to the perpetrator what the other's needs or wishes are.
The words are from a rap song and are really too tasteless to appear on this website. Look for "My way or the highway" on Yahoo or Google and you'll come up with many hits.
The song apparently has served as a basis for a parody for those who don't like the politics and "my way is the highway" attitude of George Bush.