Ipod touch problems(windows xp user)

I've been trying to download iTunes on my computer I have windows xp and everytime I get iTunes downloaded it says that the author or whatever is unknown and it also says the the file is not valid.I have no clue what to do I've had my Ipod touch for 3 days now and I can't even use it.I'm highly angry!!I'm at the point to where I just want to take my Ipod touch back to where I got it from.