Dude that cap is not worth more than $0.50, you have lots of resources in Toronto too, forget eBay. I suggest going here
http://www.a1parts.com/ they have all kinds of cool stuff not on the website. I bought a bunch of loose capacitors there really cheaply. It's worth a trip to the store just to check out the massive stock of old and weird electronics as well as the new components.
Here's the cap you need
http://www.a1parts.com/capxon/index.html 2.2uF 50V. $0.24 each.The radio will sound like crap if that cap is dried up, but yes it could also be the speaker.
Why not disconnect one lead to the speaker and try to hook it up to something else (like a stereo at low volume), just to double check that the speaker really is bad, before getting it all wet.