Rcd 210 radio without aux

[Mr.G24]

Hi,so i have a RCD210 radio fitted in my 2009 Jetta 5,but i dont have a AUX socket in the car,when i press media on my radio it does not bring up AUX selection,which i take i don't have that function on the radio.i wanted to get a AUX/USB cable that connected at the back of the radio,but i was told that if the radio does not show AUX it will not help adding a AUX connection,which i cant do,so i will have to upgrade to a rcd 310 perhaps,but still i dont have an input in my car so i can plug in a 3.5mm jack in AUX fitting or USB,how can i go around this getting to use a usb?if i do upgrade to a rcd310 can i plug in a AUX/USB connector cable in that radio?
some help and advise will be much appreciated.