How can I back up all my apps in IPad 2 ?

I need to back up all my apps from my ipad2 and thanks / because of a glitch in the operating system I had a an dollar account in Tanzania (weird I know) and apple cannot give me access to my apps to download again (should they be deleted or I upgrade) as I live in the k and now have a UK apple App Store account in sterling for purchases.

Please assist as all my dollar purchases are gone in the apps store purchased page. Apple support even managed to delete all my sterling k apps store purchases now too. It has been a nightmare.