Ivan,
Victor is absolutely right about the version numbers (and I agree with his suggestion about sticking with 2.x until 3 goes final). Also as far as not seeing the update in the update manager, I’m asumming you saw this link:
https://www.genuitec.com/forums/topic/update-site-search-doesn-t-list-2-7-0ga-closed/
and if that didn’t work, the quick way is to downlaod MyEclipse 2.7 GA Manual Install (its a zip). Then unzip it someplace, and go into your <eclipse install>\links directory, and edit the MyEclipse file, and change the path to point to the new location… walla all done.