It can be done with a cordless drill. The problem I ran into while doing mine is that the 1.2 mm drill bit I bought was too small for the chuck in my drill. So I went for the smallest size it would hold, which was 1/16" (1.6 mm). However, drilling both holes this size has resulted in an extremely airy draw. So I will have to figure out a good way to fix that, probably fill the holes with JB Weld and try to re-drill with the 1.2 mm bit in a pen vice. My temporary solution is to partially cover the holes with some electrical tape.
So my recommendation if you don't have access to a drill press is to just use a cordless drill, but make sure it will securely hold a tiny drill bit. A dremel might work too, but I can see it being difficult if you cant control the speed with finger pressure like on a drill. You will want to start out slow to get the hole started so the bit doesn't kick out and put a big nasty scratch along the side of the IGO.