New Soundsystem Question ;)

Hi guys im currently awaiting for a new sound system atm, its a logitech z-2300 for the record, my old one was a logitech Z-3, the two satellites still work but the sub doesnt, this was my reason for buying a new system, also for more bass
Any way the question is, is there any adapter i can buy to plug in to lots of speakers into my one speaker port on the back of pc, thanks very much