Cross DJ novice...

Hi.
Im new to all this....just purchased licence/software version only of Cross DJ from mac Apple app store and realise i need an audio interface.
I see there are 2 types available....including one make(UM46MK2) from a merchant for mixvibes in australia which is where i am and unfortunately i can't see it is for single sale as it comes bundled with a pack and i already have Cross DJ software installed on my macbook pro...so i need an audio interface.
I see the UM46MK2 audio interface is for a 4 channel mixer and you can add Cross DJ sampler to it also and is that one comparable with Mac OS X?
Or is the other audio interface only suited/compatable to mac OS X?
I can't see that model for sale anywhere in australia....in the mix vibes merchant/re-seller catalogue either......and is this USB audio interface as easy to connect RCA leads from and to my Amplifier with speaker so i can cue in mix in track in left ear and hear playing track in speaker connected to amp in right ear?
Is it as easy as that?
I would appreciate some feedback/answers to these questions as i want to get started on this ASAP!
Regards.
Jonathon.
Im new to all this....just purchased licence/software version only of Cross DJ from mac Apple app store and realise i need an audio interface.
I see there are 2 types available....including one make(UM46MK2) from a merchant for mixvibes in australia which is where i am and unfortunately i can't see it is for single sale as it comes bundled with a pack and i already have Cross DJ software installed on my macbook pro...so i need an audio interface.
I see the UM46MK2 audio interface is for a 4 channel mixer and you can add Cross DJ sampler to it also and is that one comparable with Mac OS X?
Or is the other audio interface only suited/compatable to mac OS X?
I can't see that model for sale anywhere in australia....in the mix vibes merchant/re-seller catalogue either......and is this USB audio interface as easy to connect RCA leads from and to my Amplifier with speaker so i can cue in mix in track in left ear and hear playing track in speaker connected to amp in right ear?
Is it as easy as that?
I would appreciate some feedback/answers to these questions as i want to get started on this ASAP!
Regards.
Jonathon.