DAC for entry level system


Hello,
I have an entry level system.
Speakers: Vienna acoustics Bach.
Plinius 8100 integrated amp.
Arcam CD72 player.
Logitech squeesbox touch.
I would like to buy a DAC to my system(prefer used to get more for the money), but I don’t know what price level of DAC will get me much better result compare to the internal DAC that I have now in the Arcam and the Logitec. Will(example of price groups) $179 HRT music steamer II will do it? Or $379 Musical fidelity V-DAC MKII, or $649 Simaudio 100D, or $995 Rega dac.
Thanks.
bedel
The NuWave for $600-$650 would be used. I recently got a mint unit for under $650 shipped. Some people got them for $695-$795 new w/ trade-ins so if you are patient you can find a great deal on a used one.
Thank's Dragon1952. just one more question for you. Are you using the balance output or the non balance output of the Newave? Since I don't have balance input in my amp, I wanted to ask you if you checked both of them in your system, and if you found one of them better then the other one?
Thanks.