wireless signal strength

Hi folks,

I have a Dynamode Router BR 6004 WG1 and a Dynamode 54mbps WL G1 7005 USB
adapter. The router is less than 20 feet away in the next room, and my
signal is constantly low or very low and occasionally no signal. Even when
the computer is taken into the same room as the router, the signal strength
although dose hit very good signal it falls back to low most of the time.

The download speeds are fine whether its low or good signal.

My question is this,

can any changes be made within the setting of the router to achieve a
stronger signal or is this router just rubbish and I should replace it, or
would a better USB adapter be the answer?

Regards
Scott