Hi Klaus,
Using a bias resistor doesn't change the input range of the board, so it's still -10..+10V (of course you have to configure those parameters in your software, too).
I doubt that 8.2 kOhm is enough for the input resistor. In most cases higher values than this give better results.
You can learn more about this topic in this Application Note:
Field Wiring and Noise Considerations for Analog Signals
http://zone.ni.com/devzone/conceptd.nsf/2d17d611efb58b22862567a9006ffe76/01f147e156a1be15862568650057df15?OpenDocument
If you just need specs of your board, have a look at the manual:
http://digital.ni.com/manuals.nsf/websearch/AB6BECBCD482365286256EC900675A0F?OpenDocument&node=132100_US
Richard H.
National Instruments