New speakers etc but don't know how to connect the sub!

Hello all, I have a Marantz 4300 av amp and recently got Mourdant short premier av speaker package. My problem is the connection from my previous sub is totally different(a single cable connection)and my amp has only one connection for the sub but the new amp has 2. The new sub has L+R connections but no single cable connection. The (very poor) instructions state I can connect the sub to the other satelite inputs, but these are normal cable connections i.e. the ones you normally connect to speakers??? My amp doesnt have these either? I'm totally lost with it. My girlfriend will go off the deep end if I dont sort it cos' I bugged her so much to get the kit
Any help would be great

Cheers all