Upgrade which one first, to be wise

Hi all

I need advice here. Here's the thing I am thinking for upgrading my SB3 after I found out that it's sound is very much in the same level with my new LG DVD player costing for only about $39. I use the SB3 with external DAC I bought from ebay (shek d1 $190). It sounded better then the internal SB3 DAC and better than my old chinese DVD player. I went to local hifi store and bring back 2 DAC, only the more expensive one Altis $680 sound a little bit better the other $300 sound worse. But only after I use my Copperline mains lead make me miss the Altis, not so much though.
I also consider buying Transporter suspecting that the weakest link in my system is the source.

I use Consonance a100 hybrid integrated and Vienna acoustic Haydn. but for $2200 USD the store owner said I could trade in my Vienna for SF Auditor M.

I really appreciate any opinion

sincerely
wun