your hitachi drill should be able to pound out a few holes. Its not going to be a worldbeater by any stretch of the imagination but if you drill a few holes a trip, I feel like it should suffice. I've seen smaller makitas, hitachis, craftsmans on the ice for years turn ice augers. They don't get very many holes, and most were attached to 6">= bits.
Go slow. if you can vary the speed pick the lowest speed. Thats the best thing you can do to get the most use out of a drill.
lastly do not buy a harbor freight jobby. it will suffice for hanging pictures but the type of abuse drilling holes does, it will not last long. Lots of pinch points, main brain in the handle burn out quick. Its got a good battery but not enough to make up for the mediocre components.