My NOOKcolor isn't doesn't get as solid a signal as my laptop, but I can certainly get more than 5 feet with it! My wireless access point is in my basement, and I can move around on the 2nd floor with no dropped signals.
I'd suggest trying for an exchange, if you can. There's not a lot of troubleshooting you can do with the stock B&N firmware, short of restarting the NC and your wireless equipment.
I have excat the same problem