Yup. Just noticed this thread and perhaps a bit too late for your trip. Probably the most well known shop in Townsville is Coffee Dominion downtown. Its just off the Flinders Mall across from the "sugar shaker". Holiday Inn. They roast there own beans and have knowledgeable staff. They even offer an Espresso Academy on Thursday nights, of which I am a graduate *;). I walked passed the shop the other day and happened to see a brand new GPP Pro sitting on the display shelf waiting for a new owner. Pretty rare to see these things in TSV.
I actually lived on Maggie for 5 years but cant really reccommend anywhere. However, that was a while back and perhaps times have changed. Sorry, cant help you with that one... Perhaps the coffee might not end up being up to scratch but the island will make up for it in other ways. *:)