Well, 8% per annum is equal to 2% per quarter, I think. So every quarter you're multiplying your balance on hand by 1.02. You just have to figure out how many times you need to repeat that multiplication. See the pdf.
I just asked my computer to do the last step. Aren't you glad we don't have to look up logs in tables and interpolate them, like our parents did?
Gold Coast? I think there's a place in Australia by that name.