There are many sources for caps, but one I and many others like, and that has good explanations of the different types, is JustRadios http://www.justradios.com/

As to the electrolytic can cap, yes, it needs to be replaced, but the easiest way today to do it, is to add modern 'lytics under the chassis (they are MUCH smaller than the old can), remove the leads from the old can, and leave it in place for appearance. It's probably a triple electrolytic so you'd be replacing it with three little new ones.

Reece