Not impossible. If the printers are not wireless, but the box says they are AirPrint compatible then you got sold the wrong printers. There are two models of the 6500, one ends in E710a, and the other E710n. Only the n model has wireless.
Assuming you ended up with the wrong model, you should be able to exchange them. But check the box carefully. There is a good chance it is the same box, with a discrete checkmark somewhere specifying the exact model.
If the printer is not wireless, and you can't exchange it, all is not lost. But you will need a computer that stays online all the time, has the printer drivers installed, and is on the same network as the iPads.
If you do that you can use the Print'n'Share app along with the computer program available from their site. Another option is a program on the computer that pretends to be an AirPrint printer. For Mac OSX, Printopia is an excellent choice. There is a PC program called Airprint Activator that should work for Windows.
But your iPad must be on the same network as the computer. If the wireless router creates a separate network, one that you can't see the same resources that you computers can, then it won't work.
There are probably ways to work around that, but without knowing more about your network I'd be guessing even more than I am now.