Hotel offers free wifi access. Just across the Hannover main station (Hauptbahnhof). I really enjoy this hotel because of it's excellent location. S-Bahn S5 takes you to the airport in 16 minutes.
If the double room is only a few Euro more, choose that over the single room. Double room size is 2-3x larger than single and you get 2x the free goodies in the minibar!
Rooms are good enough to just go to sleep. Cozy rooms. Excellent breakfast. The only thing that is not good in this place is the coffee. Get it somewhere else :)