Most of the numbers for travel time were based off of THIS paper. I've been meaning to run my own calculations to verify the figures I estimated from that. The actual numbers will be accurate on posting.

As for the black hole cost, the proposal says they've already tested their process for making black holes, which suggests they already have one lying around somewhere (probably inside an asteroid). Once you have one black hole, making more of them is easier. I can go into some more detail though if necessary.

EDIT: Rough calculations: Accelerating under 1g until the halfway point is reached (2 lightyears) gives you a top speed of 0.87c, and takes about 2.5 years from the ship's perspective and 3.5 years from Earth's. Double these times for the 1g deceleration, and you get 5 years on ship and 7 years on Earth. At a speed of 0.87c, the Lorentz factor is very nearly 2 (it's a little bit more). 130 petawatts, even if not all of it is being due to limits in efficiency, is more than enough to keep 1,800,000 metric tonnes moving at 1g.