Don't know whether to upgrade my IPad to an IPad Air 128GB or a 11" Macbook Air. Can I have the IPad connected to a device to upload discs (music or Video)/ Do I need a MAc to put music o my IPod?
You will get the most mileage out of an iOS device if you have a Mac or Windows computer to sync it to. That way you can use desktop iTunes to move content around more easily. That said, the iPad is a fairly sophisticated device and works quite well on its own. You will be limited in the ways you can get content onto the device, mostly by using the iTunes app which may mean paying for your music a second time if you own it on a different way than through iTunes.
IMO tablets are great but no replacement for a computer but iPads are able to do office work, web browsing, email, etc. all on their own. A lot of the basic tasks you would ask of a computer can be done from your iPad if you want to stick to just one device.