Wait! before you drill there is one small thing you need to check ( i know this because I just drilled out my peugy fork the other day). A newer road brake's short arm reach might not be enough to actually reach down to you rim. Double check to make sure your new brakes will be adjustable to get the pads all the way on the rim.
I drilled out the fork whole to put a sweet ultegra road brake on my peugot fixie, only to find out it would not work out--not the end of the world-- because the brake pads couldn't be adjusted down far enough to not rub the tire. What a bummer. Not irrevocable damage was done to the setup, though, I just slapped the old brake back on
Shimano and Tektro both make "long reach" DP caliper brakes just for the situation you describe. They fit older bikes and current frames purposely built to have clearances for larger tires and/or fenders.
The Shimano brakes are "Ultegra quality" and the Tektros are a lot cheaper and quite functional. Nashbar sells the Tektro's as a housebrand (S/N NS-LRB) and these are on sale for only $30 a pair on their website.
As to "slapping the old brakes back on", the now oversize hole in the rear of the fork crown will allow them to move under braking loads. Get the right ones.