siberia v2 is definitely worth your bucks. its normal pricing is around rm 399. so for rm249, definitely worth your rm50 top up.
its not 5.1 or 7.1. but you can achieve a virtual 7.1 with the usb soundcard.
but if you alrdy have a good dedicated soundcard, den no point with the usb soundcard.
my point of view, save another few days of food consumption, and go for the siberia v2.