Make this microphone sound better?

Hey, I have a Shure C606 (A lower end version of the SM58 really) and currently my recording setup is pretty bad it is my Mic, plugged into my amp, plugged into my mac via headphone output! I wan't to get the quality of Tyler Wards recordings. What kit can I buy for under �150 that will improve my recordings and what software (Mac) would you recommend to record audio. Thanks, Oli