Apple products not picking up Internet from wi-fi router. Why?

I recently had someone over my house who brought an iPhone and iPad and gave her the passwords to connect to my wi-fi signal. But I also had my iPhone and iPad connected.

Three of the devices connected, but only after I unplugged the wi-fi router and replugged it. But I couldn't get her iPad (which is 1st gen) to connect to the Internet.

In fact I typically need to reset the router for her iPad to connect. So why is my router having this trouble? When I go to the nearby cafe, everyone's connected to the free wi-fi. So what gives?

What does apples one year warranty cover? - 1

I recently got a free iPhone 4 from sprint with a new 2 year contract. It's almost 2 months old, and I went to take the charger out and my whole charger port came with it. Other than that there's no damage to the phone does apples 1 year warranty cover this? If not or so is there a cost? Roughly. My sprint store apple should cover it since there isn't water damage, but I wanna make sure before I go all the way to the store to just find out they don't.Ps I didn't get insurance with the phone but they said it was okay because apples warranty.

How to delete all pictures from iPhone but get them back on?

This might be a dumb question but I need to know the answer quickly.
I'm going to NYC for vacation on Tuesday and I know I will be taking plenty of pictures. My phone keeps saying that my iCloud storage is almost used up and last time this happened, it stopped letting me take pictures.
So, I'm wondering if there's anyway to sync my pictures to my computer then clear the iPhone just for my trip and then come back home and sync all my New York pictures to my computer and then get all my old pictures back on my phone?