Your keyboard may be pretty dirty if you've had it for a while; you might want to consider replacing it. Replacements are fairly cheap and easy to do.
You'll have to be more descriptive on the audio issues for help.
Does it give some sort of error when it won't connect? Please be more descriptive.
Warranties are usually 1 year, unless you bought an extended warranty. If you bought it at a store (Best Buy) then they may have some kind of warranty program. If you bought it off the Internet, there likely isn't a place you can take it.