You need to look for Sizzix quilting dies. Here's a link to the Sizzix site, but you can probably find the dies at other resellers:
http://www.sizzix.com/shop/sizzixquilting
Yes, you will need to match the size of the cutting pads to the dies.
Go! dies are thinner so you would need some sort of a shim to use them in this cutter. Don't know if they make an adaptor or not.