New powercord for MacBook

Actually you should be careful when using a charger that doesn't come with your laptop. Apple's official word on the matter is:

Make sure the proper wattage adapter for your portable computer is used. Select the appropriate power adapter for your Apple portable computer. You can use a higher wattage power adapter, but you cannot use one with less wattage without potential operating issues. (here + discussion here).

In the good old days (Powerbooks) we used to get all sorts of odd logic board hassles when using the wrong charger. These days it does mean a slower charging time but it can also mean the (very) rare logic board damage or hardware funkiness.

Apple owns a patent on the magsafe connector and hasn't licensed anyone else to make one, I'd be very wary of buying a third party one if you find one at all.

However, best I can tell a magsafe charger from any macbook seems to work with any other one, but if you get one with less wattage than your original it will charge slower.