What do I need to set up a Live sound system?

I am going to start doing small gigs in my town and I need to know what equipment I will need. I will be using Dual JBL JRX125 speakers (500 watts each) and a Korg RADIAS Synthesizer as the primary audio source. Now would I have to get an idependent mixer seperate from the RADIAS, or since that is my only sound source is that all I need? And what would be a good 1,000 watt amp that I could get for a rather low price, that could power both of the 500 watt speakers?