Tobirama is Naruto's great grandfather

[Meowazziel]

where does it say that tobirama married an uzumaki also minato is a namikaze not an uzumaki

Nowhere does it say that. The second ''he'' that Saikyokage Kage meant, refers to Minato and the Uzumaki is Kushina.

That is impossible because of the time limit than naruto must be much older

It is possible.

If Hashirama had kids during his 20-30's and Tobirama during his 40's and his offspring except Minato, had kids late as well, than you can easily fit it all in. A difference like 20-30 years between Hashirama his grandchild Tsunade and Tobirama his grandchild Minato, could easily be made this way.