MacBook charger problem

I apologize if this post isn't in the correct area, but I'm new here

I purchased my MacBook in July 2007, and I had been having problems with my charger starting in December 2010. my laptop would charge only if the jack was in contact with the port (sorry, I'm bad with terminology) in a very specific position. it was driving me nuts, so I bought a new charger. just starting today, my new one is giving me problems.

I often use my MacBook with the extension cord when I use my MacBook sitting on my bed, and keep the "box" part of the charger on my bed rather than on the floor. unfortunately, today it fell on the floor, but I had dropped my old one many times before it started to give me problems, so I don't think this is the cause. however, even though I've tried using it both with the extension cord and the regular plug, and have tried plugging it in different outlets, what happens is that at first my computer appears to be charging, but then the light on the charger goes out after one second.

supposing there is a problem with my charger, can I get my current one fixed for free, or would I need to spend another $80 on a new one again? I don't recall an extended warranty being available for chargers, but this is getting ridiculous.