First one: Can I upgrade Windows Vista Home Basic to Windows 7 Ultimate Build 7600?
Sure you can. Personally, Id do a clean install, but thats up to you.
Second question: There's an activation that activates that build for ever? As is was the Retail or Final one..
Yes there is, its called a product key. You can buy them online or in a store on general release. You can also get keys next month if you have a Technet sub. If you install it now, you could rearm it until you do have a product key.
Any other ways are not for discussion in this forum.