Unfortuantely I think one of the only options is to get the scratches buffed out, which isn't usually an option many people decide to take, it also thins the glass and makes it more suceptable to breaking from the pressure of the water.
Have you filled the tank up yet? Often scratches look worse in an empty tank.
Another thing I have heard works is to put reflectors on the light bulbs, this means you can position the reflectors so that the light isn't shining on the scratches.
EDIT: Just realised you have a Rio 125, most fish shops sell the reflectors.
All the best,
Tim.