magsafe help!

hi everyone
my magsafe power adapter is acting funny last couple of days the light keeps coming on and off but it still shows in my laptop that is charging so i don't think is a problem with my computer because tested my computer (macbook pro 13 inch mid 2009) with another magsafe and it doesn't do that.

- now this bothers a little bit because now im wondering all the time if my computer is really charging or not. i also really want one of those new magsafe power adapter too and i don't really want drop 80 on that. so do you guys think if i take in to the apple store (i still have warranty) i would get a new charger, and would i get the new kinds?

thanks