ADVICE - Tyre/Tube size Cyclocross wheels ?

Hi All

Got the following bike and looking to swap the tyres for Conti Gator Skins.

http://www.tredz.co.uk/.Cube-Cross-Race ... _58175.htm

It currently has Ronny Rockets with 33-622 (28x1.3)

Can i fit 700c x 28 ? or do i need a 622 ???

Can someone explain the sizing also ?

Also what tubes will i need for 28 width tyres and what is currently fitted...

Thanks