Why doesn't my iPhone 4 get Wi-Fi in other rooms?

Ohkay, so, like, my iPhone 4 only gets Wi-Fi in the room where my mom has the Wi-Fi box. & sometimes it has real weak Wi-Fi service. I get Wi-Fi on my iPod & laptop in every room, including outside on my porch, but not my phone. I thought about restoring it, but I wasn't sure it would help, & plus I didn't want to lose my music that purchased from the iTunes Store. So, if you have any advise on what I could do, it would be great if you could help.

Try to see if it works better with other Wi-Fi hotsports - has better range.
If yes then it is your Wi-Fi box that should be replaced or your should buy a range extender.
I do not think that Wi-Fi range has to do with resetting the phone, but you could try - iPhone has good backup/restore option so nothing to worry about with that.