IPhone 4s and it says no Wi-Fi although I'm using Internet now?

It says no connection and I need it to download IO7

What can I do?

Whose long is the apple warranty and will a broken screen NOT replaced still the original affect the warranty

Just go into settings and connect to the Internet…
And for your second question, no.

You're probably using mobile internet without realising it - don't download anything it'll cost a bomb! Try disabling your mobile internet then see if you can connect to the net, then you'll know for sure.