oyesiji,
Update sites are not available for the latest versions of MyEclipse.You can install MyEclipse 2015 Stable 2.0 to Eclipse Luna (4.4.2) from the Eclipse Marketplace. Go to Help > Eclipse Marketplace, type MyEclipse in the Find box and install MyEclipse Enterprise Workbench 2015 from the list.
Let us know how it works for you.
–Swapna
MyEclipse Support