How to update my IPhone without a computer?

Please help I wanna download stuff

No you can't update without a computer; and since your computer was hacked I suggest you use another computer to update it. Though if you do not want to lose your purchases: music, videos, apps, etc… You can transfer them from your iPhone to the other computer before you sync it with iTunes. This will NOT work with non-purchases from iTunes, Appstore, or iBooks.