do you have a silicon case on your wiimote? if so that could be why the + and - buttons dont work. i mean they will work but you have to press them a bit better than as you would without one.
also where do you have your sensor bar positioned? below the tv? above? and with that answer, did you go into your wii settings and make sure you adjusted the sensor bar? what about the sensitivity of it? did you mess around with that?
if none of these seem to be your problem, do the obvious which is check the battery meter on the home key menu.
and again if the batteries are normal and you did all these simple troubleshooting techniques, then i suggest going back to where you got the wii from and tell them you got a "lemon" remote. they should supply you with a new one. if not then contact nintendo