From the airport
Train: Take the S13 from the Cologne Airport, which departs every 20 minutes. Alight at Hansaring and switch to U15. Get off at Köln, Christophstraße/Mediapar". From there it's a 5 minutes walk to the hotel.
You can choose between a single ticket, a day ticket or a ticket for a week. Within the ticket price, you can take the train, as well as the bus in the inner circle of Köln (Cologne) center.
Taxi: It's a 20 minutes trip, depending on traffic, and costs around 40€.