If your old CPU cooler is compatible with the AM3/AM3+ socket then you can use it on your new processor. Just make sure that you clean all of the old heatsink compound off and reapply the new compound correctly.
No your old processor was am2+ your new one is am3+ different sockets so i doubt it will be compatible. You may be able to make it worK. aftermarket coolers are only about $30
I beg to differ with you on this one. Have a look at his article on Wikipedia regarding the compatability between AM2, AM2+, AM3, and AM3+ sockets: http://en.wikipedia.org/wiki/AM3%2B#Socket_AM3.2B . The physical size and layout of the mounting holes and package sizes are all the same and, therefore, any heatsink fan assembly that works with the older sockets will work with the newest one.