Slow transfer speed with My Book live 3TB

I have recently bought a 3TB My book live network storage disc.

When i transfer files (wireless) from my computer in my home network i never reach faster speeds than 5-6MB/s. This feels very slow or is it just me having to high expectations? 

I have connected the M.B.L direcly to my router (Asus Rt-N66U - Gigabit router) via a cat6 cable. My computer has 1 gigabit ethernet card, running with windows 7. 

Feels like i should be transfering files with at least 20-25MB/s!!?? 

A´m I way wrong or is the M.B.L simply not faster than this? PLEASE ADVISE!!

Test the drive by connecting directly to the computer

after that you can diagnose any problems on network or drive