In what price range do I need to go for a Dac ?

There is a lot of variety in how DACs sound. You might just need a different flavor of DAC, not necessarily a better or more expensive one. I think the mhdt DACs are very good values and a great place to start to set a baseline to see if more is needed.

If you like your Simaudio CD player you could look at the two higher end Simaudio DAC's.

I've had Simaudio. It's not hard to beat IMO. I've got a MF V-DAC that does it for I don't know how much currently--$300?

Arnettpartners
Hard to beleive that the MF beats the Sim, which is a darn good player in itself.

DACs are intersting in that I find that very good performance can be had for not much these days most likely as a result of increased maturity associated with a large commercial market for products that use DACs. High end audio is a drop in the bucket compared to the overall market and applicability of DACs these days in computers and various digital music devices. Not to say all are good or great, but many are even by most digital audiophile standards. My $300 (used) mhdt Constantine DAC continuously amazes me how well it performs even in comparison to some of the most expensive dacs out there that I have heard. I also have an mhdt Paradisea that cost just a tad more and is also very musical.