Hello
I'm actually on my way there, I emailed the hotel and this is what they told me:
from the Station to reach the Hotel you can take the S BAHN (S1 to S8) direction OST BAHNHOF there are 4 station and it'll take about 14 minuts to reach us. Also you can take a taxi wich take 15.minuts and cost about 17.-€.
I'm currently in DFW wating for my FRA fligth