software updating iOS 5.1.1 to iOS 6

l bought an iPad 2, iPad 2 with talk, and an iPad mini. All come with iOS5.1.1. A new update was shown in the settings and it started as iOS6.1.2 and has now gone up to iOS 6.1.3. These updates are 799MB, and l have tried updating useng iTunes and the updates runs for about two or three hours either by itunes or wifi, and then reports an error.

l have now thought that maybe if l download the clossest update, which would be iOS6 and then go upwards, it would be easier, l am just using layman's logic here. But the iOS 6 is not available for download.

l am in central Mozambique, so l can not call any call center, or any of the free call centers on the websites. these ipads are less than 60 days with my family, and l am starting to wonder what to do with them, because they are loosing batery life prety bad.

Please help.