I just upgraded my macbook pro and know iPhotos no longer works and is not supported. Help

iPhoto was discontinued almost 5 years ago. It is no longer developed or sold. It was replaced by the more powerful (and free) Photos.app that comes with the OS. You can migrate to that app very simply:

Hold down the option (or alt) key and launch Photos. From the resulting menu select 'Choose Library' and point at your iPhoto Library. It will do the rest.

If you prefer not to use Photos there are several 3rd party apps that you can use. Which to choose depends on the kind of photographer you are and your budget.

iPhoto has been replaced by Photos as of OS X Yosemite 10.10.3. Click the Photos app on your Dock, find Photos in Launchpad, or search for Photos in Spotlight to see your photo library.