Help replacing my ageing amp

[Nuro]

So almost 10 years ago I bought this set: http://www.sony.co.uk/support/en/product/ht-ddw870

There is absolutely nothing wrong with it, and it gets used almost every day. The audio quality isn't perfect, but it's good enough for me. The only reason I would like to replace it, is support for modern codecs, more specifically DD+.
I'm using the Windows 8 app for Netflix, and it provides surround via DD+ but not the older DD.

I'm looking for an amp that will hopefully be compatible with my current active sub and satellite speakers. I would only replace the speakers if I really needed to. I also don't need the best, just something midway.

Any suggestions?

 

[DrJohnZoidberg]

Budget? Kind of the deciding factor here.

 

[Nuro]

No idea to be honest. I assume I'll have to spend around R5000, but less would be good. I was surprised at the price of this model - Onkyo TX-SR313. It seems to have most of what I'm looking for, for R4K at Dion Wired. But I have been out of touch with amps for some years now.

 

[Segg]

I've got the Onkyo system that came with the speakers (The HT-S4505B) I know Aquadyne is selling an unopened set for your budget, I can highly recommend them, worth every cent! It supports all the latest codecs, Audicity intelligent EQ (Brilliant feature) and an active bass