He's said hes gonna be upgrading to an interface soon but in the meanwhile, those monitors will just sit there unused, adapters for 3.5mm plugs -> 1/4" dont cost shit, maybe 5€ maximum. I'm currently using that to run audio from my integrated soundcard to my mixer, along with emu pci card (2 x 1/4" -> 2 x 1/4") for music stuff. The quality of the sound from the integrated soundcard hasn't really bothered me (as said i use it for mp3's, gaming and all taht random stuff apart from production). Though i've never even tried to produce with it, so i guess I'll believe your word for it.
But what interests me more is why RCA phono connectors?
(and btw i biasedly recommend an emu sound interface, for example the 0404 PCI is £79 at thomann)