advice on receiver speakers upgrade

Hi all
read a lot about audio stuff in this great site
Lots of info,but need help

I have a computer with a xonar d2x hooked (spdif) to dtt 3500 creative 5.1 which is actually ok in my sitting room but would like some advice on a av receiver and speakers upgrade for more clear sound and take advantage of Asus card.
I watch movies and listen to music mainly so I guess digital and analog are both required? Or should I just go all analogue?
What you guys think about this one Yamaha buy at the cheapest price, best deals, online shop - Ireland or should I buy separate?
I guess budget between 5-600 .....I know not much
Thanks

c'mon guys.....150 views and no replies?
im kind of new to decent audio techniques....anyone at least pointing me in right direction for my budget? (5=600 € equals about 700$)

thanks for reply
its got analog and coax (im told analogue much better)
I live in ireland but can buy thru internet in uk mainly