I have a Linksys WRT120N router and my WD My Book Live 1TB is extremely slow.
Transfering files from my laptop over wifi is slow. I mean slower than USB 2.0.
Well, of course it is.
USB 2.0 is 480 megabit / second max,. with a practical limit of 35-40 MByte / second.
Even a WIRED MBL will be no faster than that.
Doing it over Wireless will CERTAINLY be slower.
And keep in mind the WRT120N is only 100 mbit/second network ports, so you would NEVER see anything faster than 10 Mbyte/second…
What kind of speeds were you expecting?