New Car - Need help with aux and cd player!

Hi Guys, 

I've just bought a 2010 1.2s Polo (first car woo!) and I could use some help.

Currently the car has a RCD 210 built in, but with no AUX input. Now, I would like to upgrade the 210 to the RCD 510 and also wire in a AUX cable to a socket next to the cigarette lighter. 

So my question is, will the RCD 510 fit my car? And what's the best way of installing an AUX cable, I've seen some videos, but could someone list some parts? Like the head to mount the AUX input. 

Thanks for any help!