What to upgrade next.


This is my first foray into the forum other than reading other's post. I hope respondents will be kind! I am at the very low end of audiophile equipment and many of you may not think I am there yet when I list my equipment. The economy has become better for myself and I am looking to upgrade but not exactly sure where to go from here. I am sure I will receive many different suggestions so I plan on taking the one suggestion that I receive the most and employing it. My equipment is as follows: Denon AVRx 3500H as my integrated amp which is boosted by a Bob Carver Cinema Grand 5 which pushes 200wpc. This powers my Polk Audio RTiA7's which are my music floorstanders. When I started upgrading I chose the Polk's as they seem to punch above their weight. After months on this site I am unaware of many people who extol the virtues of the Polks so I am thinking this may receive the most as far as recommendations. I stream most of my music from my desktop and laptop. The desktop sounds like an airplane waiting to take off. I am not independently wealthy but am looking to spend between 2-3 thousand if necessary. The one thing that gives me the biggest headache at this point is music delivery as computers have glitches and my angina acts up when the music cuts out in the middle of Alex Lifeson shredding his axe. My music files range from bad copies of MP3s which are slowly being replaced to HD Audio files. Thank you for any suggestions.
dadork
Buy a good turntable and 25 of your favorite albums and you’ll be in analog heaven. 
+100 @mesch who was so helpful as my $9k system went to $13k, but brand new would have cost about $16k because I found a lot of good used deals. The key is to listen and be patient as you learn to hear more. And for the bigger items, such as preamps and amps and speakers, used is very much a good path to go, if you know what you're looking for.
Dadork - here is my 2 cents:

a 10 K budget can go a long way. Your Source is critical - most people under estimate the benefit of a Streamer DAC combined. I have used LUMIN as my source for over 6 years. Very happy with quality and durability- their entry level unit is the LUMIN D2 at $2300.
I use it in my second system - it has to be hard wired to my router for best quality - has the Wolfson DAC - I stream Tidal HiFi with MQA. This source is so good - I retired my turntable.

For amplification - this is dictated by your speaker demands. I push Magnapans - the 1.7i to be specific - and they only cost $2300 new. . I use Krell integrated amps to push both systems but they are expensive (Krell S 550i bought used for $2900 and the new Krell K300i for $7000). The Maggie’s are very inefficient but sound amazing if given enough power. I have enough power. Your speakers are much more efficient - so your power demands are much less stringent. A good used Integrated amp is the way to go - look for one here on Audiogon. Bryston, Marantz (Ruby) and Luxman make great integrateds. A ‘box speaker ‘ I like is made by LSA - I have a set in my bedroom - Living Sound Audio. They can be had used - got mine at $750 for the pair at Audiomart.

my two channel set up works great for my movies, so I have never gone multichannel.

just my two cents!

Happy Listening!
 Tom @tom8999 I am sure now because of all of the comments that Source as you said is the biggest issue. I have committed to buying the Bluesound Node2i as my first priority. I have just enrolled in Tidal HiFi. For the time being I will stick to my Carver Sunfire Cinema for amp so I guess that leaves pre-amp integrated amp and speakers to upgrade. Thanks!
@mesch I am committed to buying the Bluesound Node2i and getting the Tidal subscription. I think Tidal will relieve a lot of my headaches I have with my music files and give me a much better file to boot as far as Hi Fi or Hi Res. I think now I am getting a clearer picture too as why I need a pre amp as opposed to an integrated. Tell me if I'm on the right track. Seeing I have a power source for all 5 channels when in HT and of course in 2 channel for music I don't need the integrated because I am bypassing the amplification provided by the Denon integrated. If I understand the theory right I am running my music through something that muddies it up. If I just get a good pre amp that doesn't add the amplification it keeps my music files cleaner.Will it still have thew video processing or passthrough and all of the HT features that I currently enjoy?