Recording into a laptop with only one line in/line out

Hi,

I have recently took up DJing after a long break. I want to record a DJ mix, using the set up I have always used previously, two CDjs, a conventional Pioneer Mixer, a 3.5mm Jack to 2 x RCA cable and Audacity. The difference now is that I have a new laptop (with Windows 8), which only has a single input which is both headphone and the line in. When I plug the 3.5mm jack in and try to record, it just records as if it is from a microphone.

I have read on-line that I can record via a USB input. I have bought a RCA to USB cable (http://i00.i.aliimg.com/wsphoto/v0/463360128/50pcs-lot-USB-Male-A-to-TV-RCA-AV-A-V-adapter-Lead-Cable-USB-to.jpg), but I can not get a laptop to recognise a USB recording device.

Is there actually a way to record via a USB input and is that cable fit for purpose? I found this device on the web - http://www.behringer.com/EN/Products/UCA202.aspx - would this do the trick?

Appreciate your advice!

That’s how I do it.
http://www.kozco.com/tech/audacity/pix/peaveyUCA202Lenovo.jpg
Koz