When I bought my Asus DVD writer a year or two back, I was informed that Asus had just dropped their warranty from 2 years to 1 year. I guess it still is 1 year.
It looks like an issue with the lens - could be as simple as dust. If you're really happy with the drive, you could give it for servicing to an authorised centre and they should be able to clean things up. If in case they ask you to change parts etc, you're better off dumping it.