Hej fellow dj'ers at DJTT!!

I have been going around the bedroom dj'ing for a while.. and im going to have some gigs on my school when we start having some parties!

But my question here is about broadcasting my mix live via some kind of radio or such.. Im wondering if it will work this way, that i've been thinking about:

I have a DDJ-Ergo from Pioneer and a RCA to Phono (i believe it is? the normal minijack used for headphones and such..) And then use it to play on my PC speakers/Altec Lansing portable speakers (I know its a shitty setup, but what the hell.. :-))

So i was thinking that to get the output back into my computer.. would i then be able to use a phono-splitter(you know.. those you always use so you can have two headsets in one device) and then just use a normal male-minijack to male-minijack and put it into my Macbook Pro 13'' Mid 2011, it has only one port which works as in AND output

I dont know if the sound will be recognized as IN at that point, do i need some kind of special cable for that? im not that good at such things..

but short in my mind it would look like this to reroute the sound into my mac and hopefully gets recognized by the software as an INPUT:

DDJ-ERGO output - Phonosplitter - minijack cable to the speakers and to the computer - software recognizes it

Is this possible? I know its a bit complicated way (i think) but its the only option i have as far as hardware goes.. i cant afford anything atm, so if this works it would be cool :P

Thanks in advance!
- DJ Sequenzed (Mathias)