External sound card advice needed

I am currenlty using an internal sound card and the ASIO driver with Ableton 8. I’m not happy with the sound quality - when i have a few tracks loaded up i get a lot of white type noise when nothing is playing. So i’m looking at getting an external sound card for PC which will attach by USB in the regon of £70-£100. Can any body suggest any.

Thanks in advance.

Tricky price range, maybe the Audio 2 from NI for a simple 2 in 2 out for £79:

http://www.dv247.com/computer-hardware/native-instruments-audio-2-dj–66945

or if you can stretch to £150 the saffire 6

http://www.dv247.com/computer-hardware/focusrite-saffire-6-usb–67804