I really wouldn't worry about your card it may be a bit dated now but it still works fine for DVB signals.
It just the Twinhan software that's a bit variable when it comes to the Q&S readings, I've had different drivers give me readings of S3,Q22 S60,Q41 S99,Q95 all with the same set up and a great picture.
Whats important is knowing the threshold readings that the picture starts to break up at.
With my present driver a really strong signal is around S65,Q59 and threshold is S38,Q34 with Q being the most important, at 33 it will break up and usually lock up the program, at 34 its usually fine, 35 is rock solid.
My Coolsat 5000 has different Q readings but won't perform any better on weak signals other that not locking up.