Dremel is your best bet... And a set of glass bits on ebay was like 12 including shipping... they're a little on the cheap side but for the cost, they're worth it. have water inside the vase at least an inch above where your drilling and have water running on the spot you're goin to be drilling... if you follow all this, you could get a big enough hole in it in about 12 seconds. It's never taken me longer than that. I've drilled through vases, arizona bottles, beer bottles just about anything glass.
