Unfortunately,
There is really no accurate way of complete accuracy in applying these results to the larger gaming demographic outside of internet savvy gamers who post on messageboards. If I had to venture a guess though, I'd bet they wouldn't change the overall response distribution too much, but there are likely respondants we are missing on both ends of the age spectrum .
These numbers are for an even larger (qualified) sample size:
2,401 +/- 2% margin of error/95% confidence
16.590 +/- 1% margin of error/99% confidence
450 is what we used to shoot for in the internet based research I used to sell, as the cost of obtaining more than that was way more than what it was worth in terms of increased confidence - ie, most marketing/product decisions our corporate clients were making didn't need more than that