I have an IPod Touch and how do I upgrade the OS so I can download stuff that needs IOS 4 or 5 please?

You first need to figure out if you have a 1G or 2G iPod Touch. See here for help.

Identifying iPod models

If it's a 1G iPod Touch, you cannot upgrade past iOS 3.1.3.

If it's a 2G iPod Touch, it can be upgraded as high as iOS 4.2.1.

For help on updating your iPod's version of iOS, see here.

iOS: How to update your iPhone, iPad, or iPod touch

B-rock

Since you have iOS 3.1.3 I suspect you have a 1G iPod. Those can only go to 3.1.3

A 2G can go to 4.2.1

A 3G and 4G to iOS 5.

To identify yurs:

Identifying iPod models

Which iPod touch do you have? If you're not sure, take a look at this -> Identifying iPod models

This Apple article outlines the versions of iOS that will work on each iPod touch.

Notes:

• iOS 4.2 is the latest version of iOS for iPod touch (2nd generation).
• iOS 3.1.3 is the latest version of iOS for iPod touch (1st generation). If you are using an iPod touch (1st generation) with iOS 2.x or earlier, you can purchase iOS 3 from the iTunes Store. See this article for more information.

Your welcome. 🙂

B-rock